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Pathogens and symbionts in ticks: Prevalence of Anaplasma phagocytophilum (Ehrlichia sp.), Wolbachia sp., Rickettsia sp., and Babesia sp. in Southern Germany
Abstract
Tick-transmitted diseases like tick-borne encephalitis and Lyme borreliosis have been well known in Germany for decades. Ongoing research now gives an additional focus to a broad range of other bacteria and parasites in ticks like Anaplasma phagocytophilum, former Ehrlichia sp., Rickettsia sp. and Babesia sp. Knowledge about the prevalence of these infectious agents in ticks is an important prerequisite for risk assessment of human diseases. Therefore nymphs and adult Ixodes ricinus ticks were collected and examined for Anaplasma phagocytophilum (n = 5424 ticks), Rickettsia sp. (n = 1187), and Babesia sp. (n - 3113). For the detection of Anaplasma phagocytophilum, DNA from the 16S rDNA gene was amplified by nested PCR and hybridized with a DIG-labeled oligonucleotide probe. The examination of Rickettsia sp. was performed by single PCR. A partial sequence of the citrate synthase gene was amplified. As a target for the detection of Babesia sp., DNA from the 18S rDNA gene was amplified, also by single PCR. All positive PCR products were sequenced to control specificity.
... Several European studies have examined the prevalence of A. phagocytophilum in field-collected questing ticks, resulting in values between 1.0% in a study from Germany [11] and 40.5% in a study from Denmark [12]. Prevalence is typically higher in adult than nymphal ticks, as shown for example in a study from Denmark with infection rates of 14.5% in nymphs compared with 40.5% in adult I. ricinus ticks [12]. ...
... Prevalence is typically higher in adult than nymphal ticks, as shown for example in a study from Denmark with infection rates of 14.5% in nymphs compared with 40.5% in adult I. ricinus ticks [12]. Local investigations in the northern German cities of Hamburg and Hannover revealed A. phagocytophilum prevalences of 2.1% and 4.5%, respectively [13,14], in field-collected adult I. ricinus, compared with only 1.0% in a study from southern Germany [11]. In ticks collected from dogs and cats in Europe, between 1.0% and 22.3% were qPCR-positive for A. phagocytophilum, with most of the studies concentrating mainly on dogs [15][16][17][18][19][20]. ...
... In previous studies on questing female I. ricinus collected from vegetation in Germany, A. phagocytophilum prevalences between 1.0% [11] and 11.6% [45] were detected, whereas a comparably high prevalence of 40.5% was reported from Denmark [12]. In previous studies examining ticks from dogs and cats, between 0.1% female I. ricinus from the UK [15], 3.5% from Finland [20], and 22.3% from Poland [16] were found to be A. phagocytophilum positive. ...
Background
Changing geographical and seasonal activity patterns of ticks may increase the risk of tick infestation and tick-borne pathogen (TBP) transmission for both humans and animals.
Methods
To estimate TBP exposure of dogs and cats, 3000 female I. ricinus from these hosts were investigated for Anaplasma phagocytophilum and Borrelia species.
Results
qPCR inhibition, which was observed for ticks of all engorgement stages but not questing ticks, was eliminated at a template volume of 2 µl. In ticks from dogs, A. phagocytophilum and Borrelia spp. prevalence amounted to 19.0% (285/1500) and 28.5% (427/1500), respectively, while ticks from cats showed significantly higher values of 30.9% (464/1500) and 55.1% (827/1500). Accordingly, the coinfection rate with both A. phagocytophilum and Borrelia spp. was significantly higher in ticks from cats (17.5%, 262/1500) than dogs (6.9%, 104/1500). Borrelia prevalence significantly decreased with increasing engorgement duration in ticks from both host species, whereas A. phagocytophilum prevalence decreased only in ticks from dogs. While A. phagocytophilum copy numbers in positive ticks did not change significantly over the time of engorgement, those of Borrelia decreased initially in dog ticks. In ticks from cats, copy numbers of neither A. phagocytophilum nor Borrelia spp. were affected by engorgement. Borrelia species differentiation was successful in 29.1% (365/1254) of qPCR-positive ticks. The most frequently detected species in ticks from dogs were B. afzelii (39.3% of successfully differentiated infections; 70/178), B. miyamotoi (16.3%; 29/178), and B. valaisiana (15.7%; 28/178), while B. afzelii (40.1%; 91/227), B. spielmanii (21.6%; 49/227), and B. miyamotoi (14.1%; 32/227) occurred most frequently in ticks from cats.
Conclusions
The differences in pathogen prevalence and Borrelia species distribution between ticks collected from dogs and cats may result from differences in habitat overlap with TBP reservoir hosts. The declining prevalence of A. phagocytophilum with increasing engorgement duration, without a decrease in copy numbers, could indicate transmission to dogs over the time of attachment. The fact that this was not observed in ticks from cats may indicate less efficient transmission. In conclusion, the high prevalence of A. phagocytophilum and Borrelia spp. in ticks collected from dogs and cats underlines the need for effective acaricide tick control to protect both animals and humans from associated health risks.
Graphical Abstract
... Due to the competence of at least two tick species to spread and transmission of B. microti in Europe, I. ricinus and I. trianguliceps [2,6], it seems more prevalent in Western Europe than other parts [28]. It is recorded in all countries of Central Europe in ticks and mammals hosts -Poland [6,19,[29][30][31][32][33][34], Germany [11,16,19,35], Czech Republic (former Czechoslovakia) [36,37], Slovakia [38][39][40], Hungary [21,28,41] and Austria [42] (Table 2 a,b). Several studies concerned the Holarctic distribution of the parasite, and the molecular investigation show the genetic diversity. ...
... Due to the competence of at least two tick species to spread and transmission of B. microti in Europe, I. ricinus and I. trianguliceps [2,6], it seems more prevalent in Western Europe than other parts [28]. It is recorded in all countries of Central Europe in ticks and mammals hosts -Poland [6,19,[29][30][31][32][33][34], Germany [11,16,19,35], Czech Republic (former Czechoslovakia) [36,37], Slovakia [38][39][40], Hungary [21,28,41] and Austria [42] (Table 2 a,b). Several studies concerned the Holarctic distribution of the parasite, and the molecular investigation show the genetic diversity. ...
... The prevalence in ticks population in Poland varied from 2.8 to 16.3%, rarely higher; moreover, the lowest values were noted in central and northern parts of the country [44,45], the highest in southern and western parts [5,33,34,43]. In Germany the prevalence of infection in ticks was in the range 0.1 to 3.5% [19,48], similar values were noted in Czech Republic and Hungary, 1.5% and 0.33% to 3.5% respectively [21,37,41] (Table 2a). ...
In the Central European conditions, three species of Babesia have epidemiological significance as human pathogens-Babesia divergens, B. microti and B. venatorum. Tick Ixodes ricinus is considered as their main vector, wild mammals as the animal reservoir. The zoonotic cycles of small and large Babesia differ in details. Due to the lack of transovarial mode transmission in small species B. microti, the circulation goes mainly between immature ticks and vertebrate hosts; pathogen circulates primarily in the cycle: infected rodent → the tick larva → the nymph → the mammal reservoir → the larva of the tick. The tick stages able to effectively infect human are nymphs and adult females, males do not participate in the follow transmission. For large Babesia-B. divergens and B. venatorum, the transovarial and transstadial transmission enable the presence of the agent in adult ticks, moreover, that larvae and nymphs feed on not-susceptible hosts. The tick stages able to effectively infect cattle and other ruminants are adult females. Resuming, pathogen circulates primarily in the cycle the ruminant host-adult female tick-the larva-the nymph-adult female of the next generation-the ruminant. Due to the compound developmental transmission has place after the outflow of a tick began feeding.
... This species is a vector of more than 40 different veterinary and medically important pathogens [11]. Dog ticks are the most important mediator of several babesiosis diseases (Babesiosis divergens, Babesiosis microti, Babesiosis odocoilei, Babesiosis canis, and Babesiosis caballi) [16][17][18][19][20][21]. In western and central Europe, a northward spread of babesiosis has been observed in recent years, likely due to climatic changes that increase ticks' survival and cause host animals to travel [22,23]. ...
... In western and central Europe, a northward spread of babesiosis has been observed in recent years, likely due to climatic changes that increase ticks' survival and cause host animals to travel [22,23]. It is also a vector of several bacterial diseases, such as granulocytic ehrlichiosis, Lyme borreliosis, tick-borne lymphadenopathy (TIBOLA), and tularemia [20,[24][25][26][27]. It has recently been shown that D. reticulatus, like Ixodes ricinus, can also transmit tick-borne encephalitis virus (TBEV) [26,28]. ...
Dermacentor reticulatus (Fabr., 1794) (Acari: Ixodidae) is parasite that spreads many diseases which are dangerous to humans and animals. Microelement lithium was found to have promising potential against the detrimental bee pest Varroa destructor. Furthermore, its effectiveness was confirmed against Dermanyssus gallinae, a major parasite of poultry, in vitro. In the present study, we investigated whether the efficacy of lithium chloride extends to other parasitic species, such as
D. reticulatus. Our results revealed, for the first time, that the effectiveness of lithium chloride extends to D. reticulatus, confirmed to have 100% mortality at a relatively high minimum concentration of 1.38 M in vitro. The 24 h and 48 h median lethal concentration (LC50) values proved to be 0.654 M and 0.481 M, respectively, for this species. Our pilot study may contribute to a better understanding of the properties of lithium ion. Furthermore, it may elicit further studies aiming to reveal whether the different environmental mineral conditions may influence the D. reticulatus population. Further studies might reveal whether lithium has any possible veterinary relevance.
Free access: https://www.mdpi.com/2075-4450/14/2/110
... Depuis l'hôte, co-feeding (Silaghi et al. 2008;Hartelt et al. 2004) Rickettsia helvetica, R. monacensis ...
... Au contraire, la transmission des virus conservés également au sein des glandes salivaires, dont celui de l'encéphalite à tiques, peut être réalisée sans délais dès que la tique commence à se nourrir (Mansfield et al. 2009 (Stuen, Granquist, and Silaghi 2013b). D'autre part, une étude menée en Allemagne par Hartelt et al., sur un échantillon d'environ 3 000 tiques, montre que le taux de présence de Babesia est de 1% au sein des tiques échantillonnées, dont 90 % des protozoaires détectés appartenant à l'espèce Babesia divergens (Hartelt et al. 2004). ...
L’augmentation des populations de tiques dans le monde, due au changement climatique et au développement de résistance aux acaricides, met en évidence le besoin de nouvelles méthodes de contrôle. La caractérisation de nouvelles cibles moléculaires aux acaricides est donc nécessaire. Les récepteurs à l’acétylcholine de type nicotinique (ou nAChRs) sont des cibles pour les pesticides (comme les néonicotinoïdes) chez les arthropodes et sont peu étudiés chez la tique. Ce sont des protéines transmembranaires formées de cinq sous-unités et qui sont impliquées dans la neurotransmission synaptique rapide. Les objectifs de cette thèse sont de caractériser les profils pharmacologiques des nAChRs neuronaux chez la tique Ixodes ricinus et d’identifier de nouvelles molécules acaricides qui pourront être utilisées dans la prévention et la lutte contre les tiques. Pour accomplir ces objectifs de thèse, une nouvelle technique a été mise au point sur cette espèce de tique, la microtransplantation de membranes purifiées provenant du cerveau (ou synganglion) de la tique et leur expression en système hétérologue. Cette technique inédite a permis pour la première fois de caractériser les nAChRs natifs de la tique I. ricinus. Nous avons démontré la sensibilité des nAChRs à différents agonistes (acétylcholine et nicotine), antagonistes (alpha-bungarotoxine et méthyllycaconitine), ainsi que la faible sensibilité à des néonicotinoïdes. Néanmoins, l’utilisation d’un modulateur allostérique positif (le PNU-120596) a permis d’augmenter la sensibilité des nAChRs natifs à ces molécules. De plus, nous avons identifié plusieurs sous-unités de nAChRs chez la tique I. ricinus. En particulier, nous avons réalisé le clonage de sous-unité de nAChRs. En complément de ces études in-vitro, nous avons mené de nouvelles expériences comportementales sur des tiques adultes pour observer l’effet répulsifs de composés. Pour conclure, ces travaux ont mis en évidence la présence de nAChRs au sein du synganglion de la tique I. ricinus. Les résultats obtenus grâce à leur caractérisation moléculaire, électrophysiologique ainsi que l’approche comportementale sont encourageant pour le développement de nouvelles molécules acaricides et répulsives contre I. ricinus.
... Ticks are regarded as important external parasites of animals' especially in tropical and sub-tropical zones where they transmit most of the serious diseases, among which the majority are blood parasites and Rickettsia. Blood parasites are generally transmitted by arthropods either mechanically or biologically (Hartelt, 2004). ...
... Although the major economic impact of Babesiosis is on the cattle industry, infections in other domestic animals, assume varying degrees of importance throughout the world (Kuttler, 2018;Ali, 2005). Anaplasmosis, formerly known as gall sickness, is a disease of ruminants caused by a rickettsial parasite, family Anaplasmataceae, and genus Anaplasma the microorganism is gram-negative (Hartelt et al., 2004) and infects red blood cells. ...
prevalence of blood parasites in cattle in Al Obied and Al Nohud cities in North and West Kordufan respectively. Sixty-seven blood samples were collected from each city. These samples were subjected for parasitological examination using thin blood smears which stained and microscopically examined. Blood samples collected from Al Obied city; the prevalence of protozoan parasites was 52.2%. The prevalence of Theileria spp., Babesia spp., Anaplasma spp. were 14.9%, 25.4%, 11.9%, and 2.9% respectively. Mixed protozoan parasitic infestations represented 3.0% in Al Obied city. The mixed protozoan parasitic infestations were (Theileria spp. and Babesia spp.) and (Babesia spp. and Anaplasma spp.). Samples collected from Al Nohud city; the prevalence of blood parasites was 28.4%. The prevalence of Theileria spp. was 17.9%, Babesia spp. 3.0%, Anaplasma spp. 7.5%. The mixed infestation was 1.5%. The mixed protozoan parasitic infestation was 1.5%. The mixed protozoan parasitic infestation was Anaplasma spp. and Theileria spp.
... Furthermore, we are beginning to appreciate that pathogen infection can alter the bacterial microbiota of ticks [4,6]. However, little is known about the specific interactions of members of the bacterial microbiota of ticks and their impact on disease transmission [9,10]. ...
... DF = 3, p ≤ 0.004) ( Figure 1E), suggesting the ISE6-w cell line was gradually losing the walbB infection. When comparing later passages (10)(11)(12)(13)(14)(15)(16) there is evidence of a secondary shift in Wolbachia infection density and subsequent loss of infection by passage 16, as determined by an undetectable qPCR and low number of Wolbachia cells at passage 14 in FISH images (ANOVA, F = 18.8, DF = 3, p ≤ 0.0006) ( Figure 1B,F). ...
The specific interactions of members of tick bacterial microbiota and their effects on pathogen transmission remains relatively unexplored. Here, we introduced a novel Wolbachia infection type into Ixodes scapularis tick cells and examined the antipathogenic effects on the intracellular pathogen Anaplasma phagocytophilum. An increase in A. phagocytophilum replication was observed in Wolbachia-infected tick cells. However, Wolbachia infection densities decreased when cells were serially passaged and ultimately the infection was lost. Host-cell immune response was also examined as an additional factor that could have affected A. phagocytophilum replication in Wolbachia-infected cells. In early passages post-Wolbachia infection, a decreased immune response was observed, but in later passages of cells with low Wolbachia densities, there was no change in the immune response. The results are discussed in relation to the importance of studying the interactions of the tick microbiota, the host cell, and the pathogen and the development of novel tick and tick-borne disease-control approaches.
... The order Ixodida is the only large group of haematophagous arthropods in which the status of Wolbachia infections still remains ambiguous. While many studies have reported the presence of Wolbachia in ticks using molecular methods [32][33][34][35][36][37][38][39][40][41][42][43][44][45], it is unclear whether ticks are themselves infected with Wolbachia, or if the bacteria are present within cells of species of the parasitic wasp genus Ixodiphagus [46] or other parasites of ticks such as nematodes [39] or mites. Recent studies have yielded strong indications that the latter scenario may be the correct one, as Wolbachia-positive Ixodes ricinus ticks are almost always positive for Ixodiphagus DNA [47,48]. ...
... The cell lines used in the present study were also chosen because they belong to species in which Wolbachia has been detected by molecular techniques: I. scapularis [33,44], I. ricinus [34][35][36]38,43] and R. microplus [37,41]. Other tick species reported to harbour Wolbachia DNA include the ixodid ticks Amblyomma americanum [39], Rhipicephalus sanguineus [32], Dermacentor silvarum [45] and Haemaphysalis hystricis [40] and the argasid tick Ornithodoros rietcorreai [42]. ...
Wolbachia are intracellular endosymbionts of several invertebrate taxa, including insects and nematodes. Although Wolbachia DNA has been detected in ticks, its presence is generally associated with parasitism by insects. To determine whether or not Wolbachia can infect and grow in tick cells, cell lines from three tick species, Ixodes scapularis, Ixodes ricinus and Rhipicephalus microplus, were inoculated with Wolbachia strains wStri and wAlbB isolated from mosquito cell lines. Homogenates prepared from fleas collected from cats in Malaysia were inoculated into an I. scapularis cell line. Bacterial growth and identity were monitored by microscopy and PCR amplification and sequencing of fragments of Wolbachia genes. The wStri strain infected Ixodes spp. cells and was maintained through 29 passages. The wAlbB strain successfully infected Ixodes spp. and R. microplus cells and was maintained through 2-5 passages. A novel strain of Wolbachia belonging to the supergroup F, designated wCfeF, was isolated in I. scapularis cells from a pool of Ctenocephalides sp. cat fleas and maintained in vitro through two passages over nine months. This is the first confirmed isolation of a Wolbachia strain from a flea and the first isolation of any Wolbachia strain outside the "pandemic" A and B supergroups. The study demonstrates that tick cells can host multiple Wolbachia strains, and can be added to panels of insect cell lines to improve success rates in isolation of field strains of Wolbachia.
... The order Ixodida is the only large group of haematophagous arthropods in which the status of Wolbachia infections still remains ambiguous. While many studies have reported the presence of Wolbachia in ticks using molecular methods [32][33][34][35][36][37][38][39][40][41][42][43][44][45], it is unclear whether ticks are themselves infected with Wolbachia, or if the bacteria are present within cells of species of the parasitic wasp genus Ixodiphagus [46] or other parasites of ticks such as nematodes [39] or mites. Recent studies have yielded strong indications that the latter scenario may be the correct one, as Wolbachia-positive Ixodes ricinus ticks are almost always positive for Ixodiphagus DNA [47,48]. ...
... The cell lines used in the present study were also chosen because they belong to species in which Wolbachia has been detected by molecular techniques: I. scapularis [33,44], I. ricinus [34][35][36]38,43] and R. microplus [37,41]. Other tick species reported to harbour Wolbachia DNA include the ixodid ticks Amblyomma americanum [39], Rhipicephalus sanguineus [32], Dermacentor silvarum [45] and Haemaphysalis hystricis [40] and the argasid tick Ornithodoros rietcorreai [42]. ...
Wolbachia are intracellular endosymbionts of several invertebrate taxa, including insects and nematodes. Although Wolbachia DNA has been detected in ticks, its presence is generally associated with parasitism by insects. To determine whether or not Wolbachia can infect and grow in tick cells, cell lines from three tick species, Ixodes scapularis, Ixodes ricinus and Rhipicephalus microplus, were inoculated with Wolbachia strains wStri and wAlbB isolated from mosquito cell lines. Homogenates prepared from fleas collected from cats in Malaysia were inoculated into an I. scapularis cell line. Bacterial growth and identity were monitored by microscopy and PCR amplification and sequencing of fragments of Wolbachia genes. The wStri strain infected Ixodes spp. cells and was maintained through 29 passages. The wAlbB strain successfully infected Ixodes spp. and R. microplus cells and was maintained through 2-5 passages. A novel strain of Wolbachia belonging to the supergroup F, designated wCfeF, was isolated in I. scapularis cells from a pool of Ctenocephalides sp. cat fleas and maintained in vitro through two passages over nine months. This is the first confirmed isolation of a Wolbachia strain from a flea and the first isolation of any Wolbachia strain outside the "pandemic" A and B supergroups. The study demonstrates that tick cells can host multiple Wolbachia strains, and can be added to panels of insect cell lines to improve success rates in isolation of field strains of Wolbachia.
... Tick microbial diversity and composition has mostly been characterized by sequencing of the 16S rRNA gene (Bonnet and Pollet 2021). Some of these studies have used culture-independent approaches and Sanger sequencing (Clay et al. 2008;Hartelt et al. 2004;Moreno et al. 2006;Schabereiter-Gurtner et al. 2003;Van Overbeek et al. 2008), but most have used bacterial DNA metabarcoding (e.g., Andreotti et al. 2011;Barraza-Guerrero et al. 2020;Beard et al. 2021;Budachetri et al. 2014;Carpi et al. 2011;Clayton et al. 2015;Gall et al. 2017;Guizzo et al. 2020;Heise et al. 2010;Lalzar et al. 2012;Narasimhan et al. 2014;Ponnusamy et al. 2014;Qiu et al. 2014;Sakamoto et al. 2020;Sperling et al. 2020;Zhang et al. 2020). One study performed DNA metabarcoding of various lineages (Bacteria, Archaea, Fungi and protists) (Landesman et al. 2019), whereas a couple of studies used shotgun metagenomics to analyze Bacteria and Archaea (Nakao et al. 2013) or only Bacteria (Díaz-Sánchez et al. 2019), and two studies analyzed bacterial transcriptomics (Hernández-Jarguín et al. 2018;Vayssier-Taussat et al. 2013) (reviewed in Narasimhan andFikrig 2015 andWu-Chuang et al. 2021). ...
It is a volume of the Journal of the Florida Mosquito Control Association. The JFMCA Vol. 71, 2024 included 4 reviews and opinions, 5 articles, 2 scientific notes, and annual meeting abstracts.
... The vector I. ricinus is widespread throughout Germany and detection rates of A. phagocytophilum in I. ricinus range between 1.9% and 5.4% [28][29][30]. Although TBF is an emerging disease in the German small ruminant population, knowledge about the distribution of A. phagocytophilum in German sheep flocks is still limited. ...
Tick-borne fever in sheep is caused by Anaplasma phagocytophilum and this obligate intracellular bacterium multiplies mostly in neutrophil granulocytes of its host. In Europe, the pathogen is mainly transmitted by the tick species Ixodes ricinus. Data on the dissemination of A. phagocytophilum in the German sheep population are scarce. Hence, this pilot study aimed to investigate the presence of A. phagocytophilum in ovine serum samples retrospectively. The use of sera is beneficial because the specimens are available in large numbers and usually stored over a long period of time. Ten sheep flocks located in five federal states of Germany (Baden-Württemberg, Bavaria, Lower Saxony, North Rhine-Westphalia, Schleswig-Holstein) were included in the investigations, due to the high intra-flock seroprevalence (>63%) of antibodies against the Anaplasma species. In total, 357 serum samples from seropositive sheep were analysed by 16S rRNA real-time PCR. DNA of A. phagocytophilum was detected in two ewes from the same farm in the northern German federal state of Schleswig-Holstein and represented an overall detection rate of 0.6%. Serum samples can be used to determine A. phagocytophilum, but sensitivity might be reduced in comparison to whole blood samples. Moreover, the sampling time may influence the detection of A. phagocytophilum in sheep, due to the seasonal pattern of tick activity in Germany. Our results support the findings of previous studies and demonstrate that A. phagocytophilum is also present in sheep from northern Germany (Schleswig-Holstein).
... In Belarus, B. microti and B. venatorum were detected with prevalence of 0.7 and 0.4 %, respectively (Reye et al. 2013). In southern Germany, Hartelt et al. (2004) found that 1.0 % of tested I. ricinus ticks were infected with Babesia spp. In urban areas around Leipzig, Munich and in the Saarland in eastern Germany, Silaghi et al. (2012) found ticks infected with several Babesia species (B. ...
Ticks are ectoparasitic arthropods of great medical and veterinary importance and are important vectors of several pathogens that affect livestock, humans, and pets. Nevertheless, the requirements of individual tick species for climatic factors for tick survival and seasonality and the temporal dynamics of tick-borne pathogens have still not been sufficiently explored, especially in areas with the simultaneous occurrence of several tick species. When the occurrence and ecology of a single tick species are studied at the model site, all the factors which determine their occurrence must be taken into account during the study. Research at the site with the sympatric occurrence of different tick species eliminates the need to study all other factors (biotic and abiotic) that affect the occurrence of a given species in a particular locality because these species are present at the same site under the same environmental conditions. These locations are therefore highly appropriate for the research of seasonal activity that is related to climatic factors. As the host range of tick species overlaps at these locations, this is highly useful also for studying pathogen flow between individual tick species. In the present study, we evaluated the influence of the most important climatic conditions, such as temperature, relative humidity, and saturation deficit for each tick species individually. Except for the coldest parts of the year, we observed a year-round occurrence of individual tick species, with species-specific differences in temporal distribution. Ixodes ricinus was the most common species, followed by Haemaphysalis inermis, Dermacentor marginatus and D. reticulatus. Altogether, 660 ticks were examined for the presence of zoonotic bacteria and protozoans. The widest spectrum of tick-borne pathogens was detected in I. ricinus. The highest was the prevalence of spirochetes from Borrelia burgdorferi s.l. complex (12.43 %), with a predominance of B. garinii and B. afzelii, followed by Babesia spp. (7.73 %) represented by B. microti and B. venatorum. Anaplasma phagocytophilum was confirmed in 2.76 % of tested ticks. The presence of co-infection with Borrelia spp. and Babesia spp. was recorded in I. ricinus (1.1 %). We also confirmed the presence of borreliae in D. reticulatus and H. inermis for the first time in Slovakia. The results confirm that I. ricinus is epidemiologically the most important tick species in Slovakia and Central Europe.
... In Germany, A. phagocytophilum was identified in I. ricinius across the country with detection rates between 1.9% and 5.4% [42][43][44]. Although A. phagocytophilum has been well described in domestic animals [19,20,25,45] and wild ungulates [9,46], knowledge of the occurrence of the pathogen in German sheep and goat flocks is still limited. ...
Knowledge about the distribution of Anaplasma spp. in small ruminants from Germany is limited. Therefore, serum samples were examined from 71 small ruminant flocks (2731 sheep, 447 goats) located in the five German federal states: Schleswig-Holstein (SH), Lower Saxony (LS), North Rhine-Westphalia (NRW), Baden-Wuerttemberg (BW) and Bavaria (BAV). Antibodies to Anaplasma spp. were determined by a cELISA based on the MSP5 antigen. A risk factor analysis at animal and flock level was also performed. Antibodies to Anaplasma spp. were detected in 70/71 flocks without significant difference in the intra-flock prevalence (IFP) between the federal states. The mean antibody levels from sheep were significantly lower in northern Germany (LS, SH) compared to west (NRW) and south Germany (BW, BAV). Sheep had a 2.5-fold higher risk of being seropositive than goats. Females and older animals (>2 years) were more likely to have antibodies to Anaplasma spp. in one third and one quarter of cases, respectively. Flocks used for landscape conservation had a five times higher risk of acquiring an IFP greater than 20%. Cats and dogs on the farms increased the probability for small ruminant flocks to have an IFP of above 20% 10-fold and 166-fold, respectively. Further studies are necessary to assess the impact of Anaplasma species on the health of small ruminants in Germany.
... The genus Wolbachia, predominantly carried by insects, but also found in other arthropods and nematodes, comprises a wide range of "supergroups" (high-level clades) with a variety of parasitic, mutualistic or ambiguous relationships with their invertebrate hosts. A number of studies have reported presence of Wolbachia DNA in I. ricinus ticks from Italy, Germany, France, The Netherlands and Morocco [40][41][42][43][44][45][46]. However, as ticks can themselves be parasitised by insects, namely the wasp I. hookeri, as well as by nematodes and mites, it is unclear whether or not Wolbachia ever naturally infects tick tissues. ...
Red squirrels (Sciurus vulgaris) are native to most of Eurasia; in much of the United Kingdom, they have been supplanted by the non-native grey squirrel, and are considered an endangered species. Very little is known about the range of tick-borne pathogens to which UK red squirrels are exposed. As part of trap-and-release surveys examining prevalence of Mycobacterium spp. in red squirrel populations on two UK islands, Ixodes ricinus ticks were removed from squirrels and PCR screened for Borrelia spp., intracellular arthropod-borne bacteria and the parasitic wasp Ixodiphagus hookeri. At both sites, the most commonly encountered tick-transmitted bacterium was Borrelia burgdorferi sensu lato (overall minimum prevalence 12.7%), followed by Anaplasma phagocytophilum
(overall minimum prevalence 1.6%). Single ticks infected with Spiroplasma were found at both sites, and single ticks infected with Borrelia miyamotoi or an Ehrlichia sp. at one site. Ticks harbouring Wolbachia (overall minimum prevalence 15.2%) were all positive for I. hookeri. Our study shows that UK red squirrels are potentially exposed to a variety of bacterial pathogens via feeding ticks. The effects on the health and survival of this already vulnerable wildlife species are unknown, and further studies are needed to evaluate the threat posed to red squirrels by Borrelia and other tick-borne pathogens.
... 54 Similarly in Bavaria, Germany a prevalence of 2.9% in I. ricinus ticks was reported, 55 with prevalences ranging from 1 to 4.5% in different parts of the country in other studies. 56,57 A study from central Italy found that 10.4% of tick samples collected from urban domestic dogs were positive for A. phagocytophilum 58 and another study in Northeastern Italy conducted between 2011 and 2016 indicated that 3.29% of the ticks collected during this period were positive for A. phagocytophilum. 59 Prevalences clearly vary greatly geographically, 13 indicating a need for country specific surveillance and large sample sizes with a broad geographic focus. ...
Background:
Anaplasma phagocytophilum is the etiological agent of canine granulocytic anaplasmosis in dogs and causes human granulocytic anaplasmosis (HGA). Tick-borne anaplasmosis has been recognised as an emerging zoonotic health concern worldwide. The aim of the present study was to determine the prevalence of A. phagocytophilum in ticks collected from dogs in the UK and map its distribution. Routine surveillance of tick-borne disease is essential as part of a "One Health" approach to infectious disease management.
Methods:
Tick DNA samples collected in 2015 as part of a large-scale tick surveillance programme were analysed using a previously validated diagnostic quantitative PCR for A. phagocytophilum.
Results:
PCR analysis indicated that 138 out of 2994 tick DNA samples analysed were positive for A. phagocytophilum, a prevalence of 4.6% (95% CI: 3.89-5.42). Among these 138 tick DNA samples, 131 were from Ixodes ricinus, six were from Ixodes hexagonus and one was from Ixodes canisuga. Three of the I. ricinus tick DNA samples positive for A. phagocytophilum DNA were also positive for Borrelia spp. DNA and one was positive for Babesia spp. DNA, indicating co-infection. The ticks positive for the pathogen DNA were found widely distributed throughout the UK.
Conclusions:
These data provide important information on the prevalence and wide distribution of A. phagocytophilum in ticks infesting dogs within the UK.
... The microbial communities within Ixodes and Dermacentor ticks, the genera most likely to harbor Anaplasma spp. in North America, have been somewhat defined. It is accepted that ticks possess various intracellular endosymbionts, many of which belong to the order Rickettsiales (Hartelt et al. 2004;Epis et al. 2008;Carpi et al. 2011;Ahantarig et al. 2013). Ticks also carry species-specific endosymbionts, such as Francisella within Dermacentor andersoni (Clayton et al. 2015;Ross et al. 2018). ...
Tick-borne illnesses pose a serious concern to human and veterinary health and their prevalence is on the rise. The interactions between ticks and the pathogens they carry are largely undefined. However, the genus Anaplasma, a group of tick-borne bacteria, has been instrumental in uncovering novel paradigms in tick biology. The emergence of sophisticated technologies and the convergence of entomology with microbiology, immunology, metabolism, and systems biology has brought tick-Anaplasma interactions to the forefront of vector biology with broader implications for the infectious disease community. Here, we discuss the use of Anaplasma as an instrument for the elucidation of novel principles in arthropod-microbe interactions. We offer an outlook of the primary areas of study, outstanding questions, and future research directions.
... However, in our study the prevalence in a large cohort of questing ticks was relatively low (<3%). The rate of infected ticks in other European countries has a wide range, from 0.1% to 50.8% in Germany and Poland respectively [103,104]. This large variation in prevalence has been attributed to seasonal differences, patchy distribution of Babesia spp., the short lifespan of the hosts, the differences in the sensitivity of the detection methods and the selection of collection technique (from an animal host or the vegetation) [79,105,106]. ...
Human babesiosis in Europe has been attributed to infection with Babesia divergens and, to a lesser extent, with Babesia venatorum and Babesia microti, which are all transmitted to humans through a bite of Ixodes ricinus. These Babesia species circulate in the Netherlands, but autochthonous human babesiosis cases have not been reported so far. To gain more insight into the natural sources of these Babesia species, their presence in reservoir hosts and in I. ricinus was examined. Moreover, part of the ticks were tested for co-infections with other tick borne pathogens. In a cross-sectional study, qPCR-detection was used to determine the presence of Babesia species in 4611 tissue samples from 27 mammalian species and 13 bird species. Reverse line blotting (RLB) and qPCR detection of Babesia species were used to test 25,849 questing I. ricinus. Fragments of the 18S rDNA and cytochrome c oxidase subunit I (COI) gene from PCR-positive isolates were sequenced for confirmation and species identification and species-specific PCR reactions were performed on samples with suspected mixed infections. Babesia microti was found in two widespread rodent species: Myodes glareolus and Apodemus sylvaticus, whereas B. divergens was detected in the geographically restricted Cervus elaphus and Bison bonasus, and occasionally in free-ranging Ovis aries. B. venatorum was detected in the ubiquitous Capreolus capreolus, and occasionally in free-ranging O. aries. Species-specific PCR revealed co-infections in C. capreolus and C. elaphus, resulting in higher prevalence of B. venatorum and B. divergens than disclosed by qPCR detection, followed by 18S rDNA and COI sequencing. The non-zoonotic Babesia species found were Babesia capreoli, Babesia vulpes, Babesia sp. deer clade, and badger-associated Babesia species. The infection rate of zoonotic Babesia species in questing I. ricinus ticks was higher for Babesia clade I (2.6%) than Babesia clade X (1.9%). Co-infection of B. microti with Borrelia burgdorferi sensu lato and Neoehrlichia mikurensis in questing nymphs occurred more than expected, which reflects their mutual reservoir hosts, and suggests the possibility of co-transmission of these three pathogens to humans during a tick bite. The ubiquitous spread and abundance of B. microti and B. venatorum in their reservoir hosts and questing ticks imply some level of human exposure through tick bites. The restricted distribution of the wild reservoir hosts for B. divergens and its low infection rate in ticks might contribute to the absence of reported autochthonous cases of human babesiosis in the Netherlands.
... Numbers at the nodes indicate the percentages of reliability of each branch of the tree. Branch length is drawn proportional to the estimated sequence divergence Wolbachia infection, such as 0.9% in Ixodes ricinus of Germany (Hartelt et al. 2004), 1.8% in Rhipicephalus microplus of USA (Andreotti et al. 2011), 3-25% in Amblyomma americanum of USA (Zhang et al. 2011), 8% in Haemaphysalis hystricis of Malaysia (Khoo et al. 2016), and 19.2% in I. ricinus of France (Moutailler et al. 2016). Most of these Wolbachia detections described by previous studies were detected by targeting the 16S rDNA gene and reported without sequence submission. ...
The genetic identity of Wolbachia endosymbiont in Rhipicephalus sanguineus ticks was determined for the first time in Taiwan. In total 1004 Rh. sanguineus ticks were examined for Wolbachia by polymerase chain reaction assay targeting the Wolbachia surface protein (wsp) gene. The prevalence of Wolbachia infection was detected in nymphs, females, and males with an infection rate of 55.8, 39.8, and 44%, respectively. The phylogenetic relationships were analyzed by comparing the sequences of wsp gene obtained from 60 strains of Wolbachia representing 11 strains of supergroup A and 10 strains of supergroup B. In general, seven major clades of supergroup A and six major clades of supergroup B can be easily distinguished by neighbour-joining analysis and were congruent by maximum likelihood method. All these Wolbachia strains of Taiwan were genetically affiliated to supergroups A and B with high sequence similarity of 98.3–100% and 98.6–100%, respectively. Intra- and inter-group analysis based on the genetic distance (GD) values indicated a lower level (GD < 0.017) within the group A strains of Taiwan compared with the group B (GD > 0.576) of other Wolbachia strains, as well as a lower level (GD < 0.062) within the group B strains of Taiwan compared with the group A (GD > 0.246) of other Wolbachia strains. Our results provide the first genetic identification of Wolbachia endosymbiont in Rh. sanguineus ticks collected from Taiwan, and detection of Wolbachia in male and nymphal ticks may imply the possible mechanism of transstadial transmission in Rh. sanguineus ticks.
... There are two reports suggesting the possibility that female-biased sex ratios in the cat flea (C. felis) (Zurita et al., 2016) and in the sand flea (Tunga trimamilata) (Luchetti et al., 2004) could be due to Wolbachia infection, but there is a need for a systematic experimental study to Benson et al., 2004;Carpi et al., 2011;Hartelt et al., 2004;Moutailler et al., 2016;Plantard et al., 2012;Reis et al., 2011;Sarih et al., 2005; substantiate this and to identify the exact mechanism by which it is mediated. There appears to be no evidence of pathogen blocking from Wolbachia infection in ground squirrel fleas (Oropsylla montana) in the case of Y. pestis (Jones et al., 2013). ...
Ectoparasites and livestock-associated insects are a major concern throughout the world because of their economic and welfare impacts. Effective control is challenging and relies mainly on the use of chemical insecticides and acaricides. Wolbachia, an arthropod and nematode-infecting, maternally-transmitted endosymbiont is currently of widespread interest for use in novel strategies for the control of a range of arthropod-vectored human diseases and plant pests but to date has received only limited consideration for use in the control of diseases of veterinary concern. Here, we review the currently available information on Wolbachia in veterinary ectoparasites and disease vectors, consider the feasibility for use of Wolbachia in the control of livestock pests and diseases and highlight critical issues which need further investigation.
... of Babesia was found in Baden-Wuerttemberg of Germany (Hartelt et al., 2004), while infection rates for A. phagocytophilum were lower (1.9%) and for Rickettsia sp. higher (8.9%) than in our study. ...
Studies of tick-borne diseases (TBDs) in Europe focus on pathogens with principal medical importance (e.g. Lyme disease and tick-borne encephalitis), but we have limited epidemiological information on the neglected pathogens as members of the genera Anaplasma, Rickettsia, Babesia and Candidatus Neoehrlichia mikurensis. Here, we integrated an extensive field sampling, laboratory analysis and GIS models to provide first publicly available information on pathogen diversity, prevalence and infection risk for four overlooked zoonotic TBDs in the Czech Republic. In addition, we assessed the effect of landscape variables on the abundance of questing ticks at different spatial scales, and examined whether pathogen prevalence increased with tick density. Our data from 13,340 ticks collected in 142 municipalities showed that A. phagocytophilum (MIR=3.5%) and Ca. Neoehrlichia mikurensis (MIR=4.0%) pose geographically uneven risks with localized hotspots, while Rickettsia (MIR=4.9%) and Babesia (MIR=1.1%) had relatively homogeneous spatial distribution. Landscape variables had significant effect on tick abundance up to the scale of 1 km around the sampling sites. Questing ticks responded positively to landscape diversity and configuration, especially to forest patch density that strongly correlates with the amount of woodland-grassland ecotones. For all four pathogens, we found higher prevalence in places with higher densities of ticks, confirming the hypothesis that tick abundance amplifies the risk of TB infection. Our findings highlight the importance of landscape parameters for tick vectors, likely due to their effect on small vertebrates as reservoir hosts. Future studies should explicitly investigate the combined effect of landscape parameters and the composition and population dynamics of hosts on the host-vector-pathogen system.
... To validate the quality of RNA extraction from the ticks, every 10th probe of TBEV negative ticks/pools were subjected to a qualitative RT-PCR detecting a 200 bp fragment of I. ricinus 18S-rDNA, using the following primers: (forward: 5′-AGA TCG TTT CTT CCT ACT TGG A-3′; reverse: 5′-ACC TAC CAT CGA CAG TTG ATA-3′) [34]. The products were amplified (2 µl cDNA sample) using a two-step method with Ampli- Taq To validate the identified positive pools/ticks, a confirmation PCR was performed in a second, independent laboratory (Molecular Biology Laboratory, State Public Health Office, Stuttgart, Baden-Württemberg). ...
Background:
Tick-borne encephalitis (TBE) is the most common viral CNS infection with incidences much higher than all other virus infections together in many risk areas of central and eastern Europe. The Odenwald Hill region (OWH) in southwestern Germany is classified as a TBE risk region and frequent case numbers but also more severe infections have been reported within the past decade. The objective of the present study was to survey the prevalence of tick-borne encephalitis virus (TBEV) in Ixodes ricinus and to associate TBEV genetic findings with TBE infections in the OWH.
Methods:
Ticks were collected by the flagging methods supported by a crowdsourcing project implementing the interested public as collectors to cover completely and collect randomly a 3532 km2 area of the OWH TBE risk region. Prevalence of TBEV in I. ricinus was analysed by reversed transcription quantitative real-time PCR. Phylogeographic analysis was performed to classify OWH TBEV isolates within a European network of known TBEV strains. Mutational sequence analysis including 3D modelling of envelope protein pE was performed and based on a clinical database, a spatial association of TBE case frequency and severity was undertaken.
Results:
Using the crowd sourcing approach we could analyse a total of 17,893 ticks. The prevalence of TBEV in I. ricinus in the OWH varied, depending on analysed districts from 0.12% to 0% (mean 0.04%). Calculated minimum infection rate (MIR) was one decimal power higher. All TBEV isolates belonged to the European subtype. Sequence analysis revealed a discontinuous segregation pattern of OWH isolates with two putative different lineages and a spatial association of two isolates with increased TBE case numbers as well as exceptional severe to fatal infection courses.
Conclusions:
TBEV prevalence within the OWH risk regions is comparatively low which is probably due to our methodological approach and may more likely reflect prevalence of natural TBEV foci. As for other European regions, TBEV genetics show a discontinuous phylogeny indicating among others an association with bird migration. Mutations within the pE gene are associated with more frequent, severe and fatal TBE infections in the OWH risk region.
... sind der Mittelmeerraum und Südosteuropa. Anaplasma phagocytophilum und Babesia (B.) canis sind mittlerweile auch in Deutschland endemisch (Hartelt et al., 2004). Babesia canis wurde sporadisch in einigen Regionen in Deutschland nachgewiesen (Gothe und Wegerdt, 1991;Zahler et al., 2000;Jensen und Nolte, 2005;Kehl et al., 2005;Barutzki et al., 2007), unter anderem in Berlin-Brandenburg (Heile et al., 2006). ...
Due to climatic changes, the increasing import of dogs from abroad as well as increasing
tourism and freight traffic within Europe and consequently the increased spreading of possible vectors, vector-borne infections are growing in importance among dogs in Germany. In the countries of the Mediterranean region as well as in southeastern Europe, pathogens such as Leishmania infantum, Hepatozoon canis, Ehlichia canis, Anaplasma platys and Dirofilaria spp. are endemic. Anaplasma phagocytophilum and Babesia spp. also occur in central and western Europe. The aim of the study was to evaluate the risk of infection in dogs from Berlin/Brandenburg after being imported from endemic regions and after traveling to endemic regions. Sixteen countries in the Mediterranean region and southeastern Europe were defined as endemic.
The study included 345 dogs imported to Germany from endemic regions and presented at the Small Animal Clinic of Freie Universität Berlin between 2007 and 2015. It also included 303 dogs from Germany that had travelled to endemic regions and were presented between 2007 and 2018. In the case of dogs accompanying their owners on travels, 1174 test procedures were evaluated, divided into 525 direct and 449 indirect methods of detection; for the imported dogs, 1368 tests were evaluated, divided into 576 direct and 792 indirect Methods of detection.
More than one tenth of the dogs (40/303 dogs, 13%) that had travelled to endemic countries were tested positive for at least one vector-borne infection. In dogs imported to Germany from endemic countries, more than one third (122/345 dogs, 35%) had at least one vector-borne infection. The dogs imported to Germany from endemic countries were most frequently tested positive for Leishmania infantum (66/314 dogs tested for the pathogen, 21%), Ehrlichia canis (45/278, 16%) and Babesia spp. (25/251, 10%). For those dogs that had travelled to endemic countries, the tests were mainly positive for Ehrlichia canis (18/231, 8%), Leishmania infantum (14/260, 5%) and Babesia spp. (14/260, 5%). Infections with more than one pathogen, which can complicate diagnosis and cause more severe clinical symptoms, were found in 1% (4/303 dogs) of dogs that had travelled as companion dogs and in 8% (27/345 dogs) of the imported dogs. Most dogs were imported to Germany from Spain (186/345 dogs), Greece (48/345), Hungary (19/345) and Italy (19/345). Dogs tested positive for at least one vector-borne infection were mainly from Portugal (6/12 dogs, 50%), Greece (22/48, 46%) and Spain (67/186, 36%). Only countries from which at least 10 dogs were imported to Germany were considered for the omparison. The most popular travel destinations were Italy (90/303 dogs), France (53/303) and Spain (49/303). Fifty-seven of 129 dogs had travelled to two or three countries. Positive test results for vector-borne infections were most frequently found in dogs travelling to Croatia (3/15 dogs, 20%), Italy (13/90, 14%) and Spain (6/49, 12%). Only countries that at least 10 dogs had travelled to were considered for the comparison.
Due to climatic changes, the increasing import of dogs from abroad as well as increasing
tourism and freight traffic within Europe and consequently the increased spreading of possible vectors, it is necessary to protect all dogs in Germany from infections by means of ectoparasite prophylaxis, preferably with substances that have a repelling effect. Furthermore, it would be desirable to introduce official monitoring of dogs accompanying travels to endemic countries as well as registration of dogs imported from abroad, in combination with the education of owners by authorities and/or veterinarians in Germany, in order to reduce further spreading of infections and possible vectors. Vector-borne infections are important not only for veterinary medicine, but also for human medicine and public health because of the zoonotic potential of some infectious agents. Test procedures for vector-borne infections should be applied in a targeted and considered manner. This includes considering the time and location of the stay abroad and/or import, the clinical and clinicopathological findings of affected dogs and possible financial limitations of the owners.
... The detection of Wolbachia in more than 25% of the ticks from Massachusetts was not expected. Wolbachia are known to exhibit endosymbiotic mutualism with insects [55,56], and has been previously reported in other ticks [57,58], but not I. scapularis. Although Wolbachia has been known to induce resistance to dengue virus when introduced into Aedes aegypti mosquitoes [56] and other insects [55], Plantard et al. (2012) showed that Wolbachia in the I. ricinus tick, a major European vector of the Lyme disease agent, is due to the presence of the endoparasitoid wasp Ixodiphagus hookeri, and not representative of a true endosymbiont of the tick [59]. ...
Background:
The blacklegged tick, Ixodes scapularis, is the primary vector of the Lyme disease spirochete Borrelia burgdorferi in North America. Though the tick is found across the eastern United States, Lyme disease is endemic to the northeast and upper midwest and rare or absent in the southern portion of the vector's range. In an effort to better understand the tick microbiome from diverse geographic and climatic regions, we analysed the bacterial community of 115 I. scapularis adults collected from vegetation in Texas and Massachusetts, representing extreme ends of the vector's range, by massively parallel sequencing of the 16S V4 rRNA gene. In addition, 7 female I. scapularis collected from dogs in Texas were included in the study.
Results:
Male I. scapularis ticks had a more diverse bacterial microbiome in comparison to the female ticks. Rickettsia spp. dominated the microbiomes of field-collected female I. scapularis from both regions, as well as half of the males from Texas. In addition, the male and female ticks captured from Massachusetts contained high proportions of the pathogens Anaplasma and Borrelia, as well as the arthropod endosymbiont Wolbachia. None of these were found in libraries generated from ticks collected in Texas. Pseudomonas, Acinetobacter and Mycobacterium were significantly differently abundant (p < 0.05) between the male ticks from Massachusetts and Texas. Anaplasma and Borrelia were found in 15 and 63% of the 62 Massachusetts ticks, respectively, with a co-infection rate of 11%. Female ticks collected from Texas dogs were particularly diverse, and contained several genera including Rickettsia, Pseudomonas, Bradyrhizobium, Sediminibacterium, and Ralstonia.
Conclusions:
Our results indicate that the bacterial microbiomes of I. scapularis ticks vary by sex and geography, with significantly more diversity in male microbiomes compared to females. We found that sex plays a larger role than geography in shaping the composition/diversity of the I. scapularis microbiome, but that geography affects what additional taxa are represented (beyond Rickettsia) and whether pathogens are found. Furthermore, recent feeding may have a role in shaping the tick microbiome, as evident from a more complex bacterial community in female ticks from dogs compared to the wild-caught questing females. These findings may provide further insight into the differences in the ability of the ticks to acquire, maintain and transmit pathogens. Future studies on possible causes and consequences of these differences will shed additional light on tick microbiome biology and vector competence.
... In other studies from Germany, the prevalence for A. phagocytophilum in ticks varied between 1.9-8.9% [74][75][76]. In this investigation A. phagocytophilum DNA was neither detected in rodents nor in ticks. ...
Background
Rodents are important in the life-cycle of ticks as hosts for immature developmental stages. Both rodents and ticks are of public health interest as they are reservoirs and vectors for different tick-borne pathogens (TBP). The aim of this study was to reassess the prevalence of TBP in previously studied areas of the city of Leipzig (Saxony, Germany).
Methods
In the years 2015–2017 rodents and ticks were collected in parks and forest areas in Saxony. DNA was extracted from the rodents, attached and questing ticks. Samples were screened for the presence of Anaplasma phagocytophilum, Babesia spp., Borrelia burgdorferi (s.l.), “Candidatus Neoehrlichia mikurensis” (CNM), Bartonella spp., Hepatozoon spp. and Rickettsia spp. using PCR methods. Rodent, attached nymph and questing tick (nymph and adult) samples were tested individually, while attached larvae were further processed in pools.
Results
A total of 165 rodents (Apodemus agrarius, n = 1; A. flavicollis, n = 59; Arvicola terrestris, n = 1; Myodes glareolus, n = 104), 1256 attached ticks (Ixodes ricinus, n = 1164; Dermacentor reticulatus, n = 92) and 577 questing ticks (I. ricinus, n = 547; D. reticulatus, n = 30) were collected. The prevalence levels in rodents were 78.2% for Bartonella spp., 58.2% for CNM, 49.1% for B. burgdorferi (s.l.) 29.1% for Rickettsia spp. and 24.2% for Hepatozoon spp. The minimal infection rates (MIR) in attached larvae ticks were 39.8% for Rickettsia spp., 32.7% for Bartonella spp., 7.1% for CNM and 8.8% for B. burgdorferi (s.l.) and the prevalence rates in attached nymphs were 33.7% for Bartonella spp., 52.9% for Rickettsia spp., 13.5% for CNM and 11.3% for B. burgdorferi (s.l.) Both rodents and attached ticks were negative for Babesia spp. The prevalence in questing ticks was 18.2% for Rickettsia spp., 7.3% for CNM, 6.4% for B. burgdorferi (s.l.) and 1.4% for Babesia spp. All tested samples were Anaplasma-negative. Sequencing revealed the occurrence of 14 identified species.
Conclusions
This research is the first evaluation of the prevalence for Hepatozoon spp. in rodents from Germany. In comparison to earlier studies, detected pathogens species remained the same; however, the prevalence for particular pathogens differed.
... The interactions of co-occurring endosymbionts within ticks are being increasingly studied (Noda et al. 1997;Clay et al. 2008;Steiner et al. 2008;Tsementzi et al. 2018), and mounting evidence has revealed endosymbiont roles in pathogen transmission in different tick species (Macaluso et al. 2002;Hartelt et al. 2004;Bonnet et al. 2017). For example, the increase in Rickettsia bellii in the microbiome was negatively correlated with Anaplasma marginale levels. ...
The tick Dermacentor everestianus is widely distributed on the Tibetan Plateau of China, where adult ticks usually parasitize sheep, yaks and horses. D. everestianus is able to transmit many zoonotic pathogens, including Francisella tularensis, Anaplasma ovis and Rickettsia raoultii-like bacteria, and can cause great damage to animals and human health. However, the symbionts in D. everestianus have not yet been investigated, which has hindered our understanding of the relationships between this tick species and associated tick-borne pathogens. In the current study, the Rickettsia-like and Coxiella-like symbionts in D. everestianus were identified and characterized. The results indicated that both Rickettsia-like (RLS-Des) and Coxiella-like (CLS-Des) symbionts showed 100% infection rates and displayed vertical transmission in D. everestianus. The RLS-Des showed a relatively higher abundance than the CLS-Des in D. everestianus. No tissue specificity was found for the RLS-Des or CLS-Des. These symbionts can inhabit the ovaries, salivary glands, midguts, Malpighian tubules and testes of D. everestianus. During the development of D. everestianus, the density of the RLS-Des showed more obvious changes than did that of the CLS-Des. Dramatic changes in the density of the RLS-Des were detected in the midguts, ovaries, salivary glands and Malpighian tubules when female D. everestianus were engorged and detached from the host, which suggested the potential role of these symbionts in the reproduction and development of D. everestianus. The dynamic changes in the density of the CLS-Des during feeding and reproduction of D. everestianus suggest the involvement of the CLS-Des in the reproduction of D. everestianus.
... Meanwhile Anaplasma phagocytophilum and Babesia spp. are endemic in Germany [7]. B. canis has been ascertained sporadically in certain regions in Germany [8][9][10][11][12], including the area Berlin-Brandenburg [13]. ...
Background
Canine vector-borne infections have gained importance in Germany due to growing tourist traffic and an increased import of dogs from abroad. Endemic regions for pathogens such as Leishmania infantum, Hepatozoon canis, Ehrlichia canis, Anaplasma platys and Dirofilaria spp. are the Mediterranean area and southeastern Europe. Babesia species and Anaplasma phagocytophilum are present all over Europe. The objective of this retrospective study was to evaluate the prevalence of vector-borne infections in dogs imported from defined endemic countries in the Mediterranean area and southeastern Europe.
Methods
Medical records and laboratory test results of 345 dogs that were imported to Germany from 17 endemic countries and that were presented to the Small Animal Clinic at Freie Universität Berlin between 2007 and 2015 were retrospectively reviewed. A total of 1368 test results from external laboratories were descriptively analysed including 576 and 792 test results of direct and indirect detection methods, respectively.
Results
Overall, 35% (122/345 dogs) were positive for at least one pathogen. Concurrent infections with two to four pathogens were detected in 8% of the dogs (27/345). The positive results were: L. infantum 21% (66/314 dogs; methods: PCR 20/79, IFAT or ELISA 63/308 dogs), E. canis 16% (45/278 dogs; methods: PCR 8/68, IFAT 43/257 dogs), H. canis 11% (3/28 dogs; method: PCR), Babesia spp. 10% (25/251 dogs; methods: Babesia spp. PCR 3/98, B. canis/vogeli IFAT or ELISA 22/214 and B. gibsoni IFAT 0/13 dogs), Dirofilaria spp. 7% (13/178 dogs; methods: D. immitis Ag-ELISA 8/156, Knott’s test 7/95, microfilariae PCR 5/23 dogs) and A. platys 5% (1/21 dogs; method: PCR). None of 8 tested dogs were positive in a combined Babesia spp./Hepatozoon spp. PCR test.
Conclusions
Dogs, which are imported from countries which are endemic for vector-borne infections should be thoroughly tested using direct and indirect detection methods. Potential owners of imported dogs should be informed about the diseases, risks and incubation periods.
... Different studies have shown that viral pathogens, such as Thogoto viruses, Wad Medani virus, Nairobi sheep disease virus, Crimean-Congo hemorrhagic fever virus, African swine fever virus and Tick-borne encephalitis virus [1,[6][7][8], can be found in Rhipicephalus ticks. Borrelia, Anaplasma, Rickettsia, Ehrlichia, and Babesia are a few examples of the pathogenic bacteria that have been identified in these types of ticks [9,10]. ...
Background: Ticks are primary vectors for many well-known disease-causing agents that affect human and animal populations globally such as tick-borne encephalitis, Crimean-Congo hemorrhagic fever and African swine fever. In this study, viral metagenomics was used to identify what viruses are present in Rhipicephalus spp. ticks collected in the Zambezi Valley of Mozambique.
Methods: The RNA was amplified with sequence-independent single primer amplification (SISPA) and high-throughput sequencing was performed on the Ion Torrent platform. The generated sequences were subjected to quality check and classfied by BLAST. CodonCode aligner and SeqMan were used to assemble the sequences.
Results: The majority of viral sequences showed closest sequence identity to the Orthomyxoviridae family, although viruses similar to the Parvoviridae and Coronaviridae were also identified. Nearly complete sequences of five orthomyxoviral segments (HA, NP, PB1, PB2, and PA) were obtained and these showed an amino acid identity of 32–52% to known quaranjaviruses. The sequences were most closely related to the Wellfleet Bay virus, detected and isolated from common eider during a mortality event in the USA.
Conclusions: In summary, this study has identified a highly divergent virus with in the Orthomyxoviridae family associated with Rhipicephalus ticks from Mozambique. Further genetic and biological studies are needed in order to investigate potential pathogenesis of the identified orthomyxovirus.
... Babesia spp. showed an over-all prevalence of 1.7%, similarly to Germany and Luxembourg [169,188]. Anaplasma phagocytophilum was the least prevalent pathogen in our study, with a mean prevalence of 0.8%-comparable with the 0.5-1% prevalence found in different European countries [186,189,190]. However, one of the sites displayed a 10-fold higher prevalence than average (Bilthoven 8%, Table 2). ...
... Buna bağlı olarak bu bakteri ile enfekte olmuş hastalarda, bakterinin klinik olarak hızlı tayininin yapılması oldukça önemlidir. Bu bakterinin tanısına yönelik PCR esaslı çok sayıda moleküler teknik mevcuttur [23][24][25][26]. ...
Bu çalışma, oldukça geniş bir konakçı gurubunda
enfeksiyona yol açan bir patojen olan Anaplasma
Phagocytophilum dizi seçimli DNA hibridizasyonunun voltametrik yöntemle
tayin edildiği tek kullanımlık elektrokimyasal DNA biyosensörü geliştirilmesine
yöneliktir. Herhangi bir etiketlemenin yapılmadığı bu elektrokimyasal
çalışmanın esasını DNA hibridizasyonu sonrasında Guanin bazının yükseltgenme
sinyalinin ölçülmesi ile bir dubleks oluşumunun izlenmesi oluşturur. Söz konusu
biyosensör tasarımı inozinmodifiye (guanin içermeyen) probun, kalem grafit
elektrota (PGE) immobilize edilmesi ve diferansiyel puls voltametrisi (DPV) ile
guanin yükseltgenme sinyalinin ölçülerek, dubleks oluşumu tayinini içerir. Bu
çalışmanın ilk aşamasında, Anaplasma
phagocytophilum temsil eden prob dizisi, aktive edilmiş kalem grafit
elektrot (PGE) yüzeyine yaş adsorbsiyon yöntemi ile immobilize edilmiş ve daha
sonra prob ve hedefi arasındaki hibridizasyonun varlığı 1000 mV’da gözlenen
guanin yükseltgenme sinyali ile tespit edilmiştir.
Yapılan
optimizasyon çalışmasında prob derişimi 25 µg/mL, prob immobilize süresi 6
dakika; hibridizasyon için hedef derişimi 40 µg/mL ve hibridizasyon süresinin
10 dakika olduğu gözlenmiştir. Geliştirilen elektrokimyasal biyosensörün
spesifikliği, baz sırasından bir bazın yeri (MM) ve tüm bazların yerleri farklı
(NC) olan hedef diziler kullanılarak, test edilmiştir. Ferri/Ferro siyanür
redoks sistemi altında elektrokimyasal empedans yöntemi kullanılarak yapılan
empedimetrik ölçümler ile DNA hibridizasyonunun gerçekleştirildiği ayrıca teyit
edilmiştir. Tayin sınırını (DL) belirlemek için hedef derişimi 0,78 µM ile 3,90
µM arasında değişen hedef diziler kullanılmış ve tayin sınırı 0,244 µM olarak bulunmuştur.
... Clinical signs of babesiosis such as flu-like symptoms or hemolytic anemia are usually but not exclusively limited to immunocompromised patients [2,58,59]. Carrier rates of I. ricinus ticks in Europe range around 0.2 to 3.0% for B. divergens and 0.4 to 1.3% for B. venatorum [2,[60][61][62]. There is evidence for circulation of B. divergens and B. venatorum in urban areas, given that the respective host species (cattle, ungulates) are present [2,30,63]. ...
Background
Throughout Europe, Ixodes ricinus transmits numerous pathogens. Its widespread distribution is not limited to rural but also includes urbanized areas. To date, comprehensive data on pathogen carrier rates of I. ricinus ticks in urban areas of Switzerland is lacking.
Results
Ixodes ricinus ticks sampled at 18 (sub-) urban collection sites throughout Switzerland showed carrier rates of 0% for tick-borne encephalitis virus, 18.0% for Borrelia burgdorferi (sensu lato), 2.5% for Borrelia miyamotoi, 13.5% for Rickettsia spp., 1.4% for Anaplasma phagocytophilum, 6.2% for "Candidatus Neoehrlichia mikurensis", and 0.8% for Babesia venatorum (Babesia sp., EU1). Site-specific prevalence at collection sites with n > 45 ticks (n = 9) significantly differed for B. burgdorferi (s.l.), Rickettsia spp., and "Ca. N. mikurensis", but were not related to the habitat type. Three hundred fifty eight out of 1078 I. ricinus ticks (33.2%) tested positive for at least one pathogen. Thereof, about 20% (71/358) were carrying two or three different potentially disease-causing agents. Using next generation sequencing, we could detect true pathogens, tick symbionts and organisms of environmental or human origin in ten selected samples.
Conclusions
Our data document the presence of pathogens in the (sub-) urban I. ricinus tick population in Switzerland, with carrier rates as high as those in rural regions. Carriage of multiple pathogens was repeatedly observed, demonstrating the risk of acquiring multiple infections as a consequence of a tick bite.
Electronic supplementary material
The online version of this article (10.1186/s13071-017-2500-2) contains supplementary material, which is available to authorized users.
... scapularis in the Northern America, I. persulcatus in northern Asia and I. ricinus in Europe. The prevalence of infection of ticks with A. phagocytophilum is very differentiated, from 1.0% [34] to 26.6% [35]. Many authors [16,[36][37][38] accent, that prevalence of infection varied significantly among the study sites, years and it differed between tick stages. ...
In Central European conditions, two species of Anaplasmataceae have epidemiological
significance – Candidatus Neoehrlichia micurensis and Anaplasma phagocytophilum. Tick Ixodes ricinus is considered as their main vector, wild mammals as the animal reservoir. There is presented the transstadial transmission in ticks, due to the lack of transovarial mode the circulation goes mainly between immature ticks and hosts; pathogen circulates primarily in the cycle: infected rodent → the tick larva → the nymph → the mammal reservoir → the larva of the tick. The tick stages able to effectively infect human are nymphs and adult females, males do not participate in the follow transmission. The summary of available data of different A. phagocytophilum strains associations with different hosts revealed at least few distinct enzootic cycle, concern the same ticks species and different mammal hosts. It is possible to reveal in Central Europe the existence of at least three different epidemiological transmission cycles of A. phagocytophilum. The first cycle involves strains pathogenic for human and identical strains from horses, dogs, cats, wild boars, hedgehogs, possibly red foxes. The second cycle involves deer, European bison and possibly domestic
ruminants. The third cycle contains strains from voles, shrew and possibly Apodemus mice. In Western Europe voles might be involved in separate enzootic cycle with Ixodes trianguliceps as the vector.
... Babesia spp. showed an overall prevalence of 1.7 %, similarly to Germany and Luxembourg (Hartelt et al. 2004,Reye et al. 2010. A. phagocytophilum was the least prevalent pathogen in our study, with a mean prevalence of 0.8 % -comparable with the 0.5-1 % prevalence found in different European countries ,Koci et al. 2007,Severinsson et al. 2010). However, one of the sites displayed a tenfold higher prevalence than average (Bilthoven 8 %, Table 2). ...
... They belong to the genus Rickettsia within the family Rickettsiaceae in the order Rickettsiales. Rickettsiae are classified (Dautel et al., 2006;Dobec et al., 2009;Franke et al., 2010;Gilles et al., 2008;Hartelt et al., 2004;Hildebrandt et al., 2011;Pichon et al., 2006;Pluta et al., 2010Pluta et al., , 2009Rieg et al., 2011;Schorn et al., 2011;Schreiber et al., 2014;Silaghi et al., 2008Silaghi et al., , 2011Simser et al., 2002;Wölfel et al., 2006) and locations of the investigated forestry districts in the federal State of Brandenburg (B). ...
In the last decade six Rickettsia species, including Rickettsia slovaca have been characterized in Germany. All of these species could be linked to distinct clinical syndromes in humans. However, due to lack of seroepidemiological data an estimation of the prevalence and the public health impact of rickettsial infections in Germany is difficult. The aim of the present study was to determine the seroprevalence of spotted fever group (SFG) rickettsiae in a population with an elevated exposure risk to ticks. For that purpose, 559 sera of forestry workers in the federal state of Brandenburg, Eastern Germany, were screened for SFG-rickettsiae reactive IgG antibodies. Positive sera were subsequently titrated by microimmunofluorescence assay against R. helvetica, R. raoultii, R. felis, “R. monacensis“ and R. slovaca. The total average IgG seroprevalence rate against SFG rickettsiae of 27.6% was found to be represented by 9.7% R. helvetica, 5% R. raoultii, 2.7% R. felis, 0.5% “R. monacensis“ and 0.5% R. slovaca. The remaining 9.1% positive test results were of non-differentiable origin. IgG seroprevalences ranged from 11% to 55% in the different forestry districts. Older and male participants had a significantly higher probability for seropositivity and higher anti-rickettsia antibody titer level. In addition, the number of recent as well as the recalled lifetime tick bites was significantly associated with seropositivity and higher titers against SFG rickettsiae. In conclusion, we found an unexpected high total seroprevalence against SFG rickettsiae in forestry workers and serological evidence confirming the occurrence of R. raoultii, R. felis, “R. monacensis“ and R. helvetica in the federal State of Brandenburg.
... R. helvetica infection in people is associated with a mild flu-like disease (Fournier et al. 2004), although chronic infections have been proposed to play a role in sarcoidosis and chronic perimyocarditis (Nilsson et al. 1999, Nilsson et al. 2002. The prevalence of R. helvetica DNA in the ticks in this study (9 %) was lower than usually found in Europe (Nijhof 2007, Christova et al. 2003, Hartelt et al. 2004, although this may be a result of seasonal fluctuations or, more likely, the high percentage of nymphs recovered in the present study. ...
This study shows which hard tick species (Ixodidae) were found in domestic horses in the Netherlands in 2008-2009, and what potential pathogens these ticks carried. In the period 2008-2009, 130 ticks were collected, classified and screened for the presence of DNA from specific tick-borne pathogens using PCR-RLB. The numbers of ticks of the various species found were: 68 Ixodes ricinus, 58 Ixodes spp. (57 nymphs and 1 larva), 2 Dermacentor reticulatus and 2 Hyalomma marginatum. DNA from Borrelia valaisiana was detected in 49 % of these ticks, B. afzelii in 22 %, B. burgdorferi sensu stricto and B. garinii in 3 % and 2 %, respectively. Rickettsia helvetica was detected in 9 % of examined ticks, Anaplasma phagocytophilum in 1.5 %, Babesia venatorum in 4%, and B. caballi and Theileria equi in 1.5 and 3 %, respectively. There were considerable regional differences suggesting focal distribution of these potential pathogens.
... Therefore, the MIR for I. ricinus reported here might be slightly underestimated compared to other studies. In several other studies, R. helvetica has also been found in ixodid ticks infesting wild and domestic animals in Bavaria, Berlin, Hamburg, northern, southern and south-western Germany with prevalences between 2.6% and 61% indicating a distribution of this Rickettsia species all over Germany (Eshoo et al., 2014;Hartelt et al., 2004;Hildebrandt et al., 2011Hildebrandt et al., , 2010bMay and Strube, 2014;Overzier et al., 2013;Schorn et al., 2011;Schreiber et al., 2014;Silaghi et al., 2008;Speck et al., 2013;Wölfel et al., 2006). In addition, R. helvetica was also detected in ticks of at least 24 European countries infesting various hosts including birds (Hornok et al., 2014;Lommano et al., 2014;Parola et al., 2013;Tijsse-Klasen et al., 2011). ...
Ixodes ricinus is a well-known vector of different human
pathogens including Rickettsia helvetica. The role of wild mammals in the
distribution and probable maintenance of Rickettsia in nature is still to
be determined. We therefore investigated various parasites from different
wild mammals as well as companion animals for the presence of Rickettsia.
A total of 606 I. ricinus, 38 Cephenemyia stimulator (botfly larvae), one
Dermacentor reticulatus, 24 Haematopinus suis (hog lice) and 30 Lipoptena
cervi (deer flies) were collected from free-ranging animals during
seasonal hunting, and from companion animals. Sample sites included
hunting leases at three main sampling areas and five additional areas in
West and Central Germany. All collected parasites were screened for
Rickettsia spp. and I. ricinus were investigated for tick-borne
encephalitis virus (TBEV) in addition. While no TBEV was detected, the
minimum infection rate (MIR) of I. ricinus with Rickettsia was 4.1%
referring to all sampling sites and up to 6.9% at the main sampling site
in Koblenz area. Sequencing of a fragment of the ompB gene identified R.
helvetica. Approximately one third (29.5%) of the animals carried
Rickettsia-positive ticks and the MIR in ticks infesting wild mammals
ranged from 4.1% (roe deer) to 9.5%. These data affirm the widespread
distribution of R. helvetica in Germany. One botfly larva from roe deer
also harboured R. helvetica. Botfly larvae are obligate parasites of the
nasal cavity, pharynx and throat of cervids and feed on cell fragments
and blood. Based on this one might hypothesise that R. helvetica likely
induces rickettsemia in cervids thus possibly contributing to maintenance
and distribution of this rickettsia in the field.
The impact of tick-borne diseases caused by pathogens such as Anaplasma phagocytophilum, Neoehrlichia mikurensis, Borrelia miyamotoi, Rickettsia helvetica and Babesia species on public health is largely unknown. Data on the prevalence of these pathogens in Ixodes ricinus ticks from seven countries within the North Sea Region in Europe as well as the types and availability of diagnostic tests and the main clinical features of their corresponding diseases is reported and discussed. Raised awareness is needed to discover cases of these under-recognized types of tick-borne disease, which should provide valuable insights into these diseases and their clinical significance.
As the main vector for the bacterium Rickettsia rickettsii in Brazil, the tick Amblyomma sculptum is a parasite of great public health importance in this country. Wolbachia is an endosymbiont bacterium highly widespread among invertebrates and because of its impact on its hosts' biology, form a powerful alternative for pests and disease control. The aim of this study was to investigate the occurrence of this bacterium in A. sculptum. For this, 187 adult ticks collected in two municipalities in the interior of the state of São Paulo, Brazil, were analyzed using molecular techniques and bioinformatics tools. A total of 15 ticks were positive for the presence of Wolbachia. Phylogenetic analysis on the 16S rRNA gene indicated that the Wolbachia DNA sequences obtained in this investigation belonged to different clades, probably in supergroups B and F. This was the first study to report the occurrence of Wolbachia in A. sculptum and it enriches knowledge about the susceptibility of ticks to this bacterium. Now that we know that Wolbachia can be found in A. sculptum, the objective for a next study must be to investigate Wolbachia's possible origin in this tick.
Dermacentor reticulatus is considered a significant parasite because of the many diseases it spreads, which are dangerous to humans and animals. Control by repellents and pesticides, short duration of action or environmental damage and development of resistance make it impossible to achieve sustainable control. New active substances are constantly needed, and natural agents are given priority. Lithium salts have been shown to be effective against the related bee pest, Varroa destructor , a mite species, also by contact mode of action. In the present study, we investigated whether the contact efficacy of lithium chloride extends to other parasitic species such as D. reticulatus . Our results uncovered for the first time that beyond Varroa destructor the effectiveness of lithium chloride extends to the dog tick, offering 100% mortality at concentrations of 5.52 M, 2.76 M and 1.38 M. However, further comprehensive studies under in vivo conditions are warranted to ensure the relevance for practical application.
Among blood-sucking arthropods, ticks are recognized as being of prime global importance because of their role as vectors of pathogens affecting human and animal health. Ticks carry a variety of pathogenic, commensal, and symbiotic microorganisms. For the latter, studies are available concerning the detection of endosymbionts, but their role in the physiology and ecology of ticks remains largely unexplored. This review paper focuses on tick endosymbionts of the genera Coxiella, Rickettsia, Francisella, Midichloria, and Wolbachia, and their impact on ticks and tick-pathogen interactions that drive disease risk. Tick endosymbionts can affect tick physiology by influencing nutritional adaptation, fitness, and immunity. Further, symbionts may influence disease ecology, as they interact with tick-borne pathogens and can facilitate or compete with pathogen development within the vector tissues. Rickettsial symbionts are frequently found in ticks of the genera of Ixodes, Amblyomma, and Dermacentor with relatively lower occurrence in Rhipicephalus, Haemaphysalis, and Hyalomma ticks, while Coxiella-like endosymbionts (CLEs) were reported infecting almost all tick species tested. Francisella-like endosymbionts (FLEs) have been identified in tick genera such as Dermacentor, Amblyomma, Ornithodoros, Ixodes, and Hyalomma, whereas Wolbachia sp. has been detected in Ixodes, Amblyomma, Hyalomma, and Rhipicephalus tick genera. Notably, CLEs and FLEs are obligate endosymbionts essential for tick survival and development through the life cycle. American dog ticks showed greater motility when infected with Rickettsia, indirectly influencing infection risk, providing evidence of a relationship between tick endosymbionts and tick-vectored pathogens. The widespread occurrence of endosymbionts across the tick phylogeny and evidence of their functional roles in ticks and interference with tick-borne pathogens suggests a significant contribution to tick evolution and/or vector competence. We currently understand relatively little on how these endosymbionts influence tick parasitism, vector capacity, pathogen transmission and colonization, and ultimately on how they influence tick-borne disease dynamics. Filling this knowledge gap represents a major challenge for future research.
Anaplasma phagocytophilum causes a multi-organ non-specific febrile illness referred to as human granulocytic anaplasmosis. The epidemiologic risk of the pathogen is underestimated despite human encroachment into the natural habitats of ticks. In this study, we performed a systematic review and meta-analysis to determine the global infection rates and distribution of A. phagocytophilum in tick vectors. We pooled data using the random-effects model, assessed individual study quality using the Joanna Briggs Institute critical appraisal instrument for prevalence studies and determined heterogeneity and across study bias using Cochran's Q-test and Egger's regression test respectively. A total of 126 studies from 33 countries across 4 continents reported A. phagocytophilum estimated infection rate of 4.76% (9453/174,967; 95% CI: 3.96, 5.71). Estimated IRs across sub-groups varied significantly (p <0.05) with a range of 1.95 (95% CI: 0.63, 5.86) to 7.15% (95% CI: 5.31, 9.56). Country-based IRs ranged between 0.42 (95% CI: 0.22, 0.80) in Belgium and 37.54% (95% CI: 0.72, 98.03) in Norway. The highest number of studies on A. phagocytophilum were in Europe (82/126) by continent and the USA (33/126) by country. The risk of transmitting this pathogens from ticks to animals and humans exist and therefore, we recommend the use of chemical and biological control measures as well as repellents and protective clothing by occupationally exposed individuals to curtail further transmission of the pathogen to humans and animals.
Zoonotic Babesia species are emerging public health threats globally, and are the cause of a mild to severe malaria-like disease which may be life threatening in immunocompromised individuals. In this study, we determine the global infection rate, distribution, and the diversity of zoonotic Babesia species in tick vectors using a systematic review and meta-analysis. We used the random-effects model to pool data and determined quality of individual studies using the Joanna Briggs Institute critical appraisal instrument for prevalence studies, heterogeneity using Cochran’s Q test, and across study bias using Egger’s regression test. Herein, we reported a 2.16% (3915/175345, 95% CI: 1.76–2.66) global infection rate of zoonotic Babesia species (B. divergens, B. microti, and B. venatorum) in tick vectors across 36 countries and 4 continents. Sub-group infection rates ranged between 0.65% (95% CI: 0.09–4.49) and 3.70% (95% CI: 2.61–5.21). B. microti was the most prevalent (1.79%, 95% CI: 1.38–2.31) species reported in ticks, while Ixodes scapularis recorded the highest infection rate (3.92%, 95% CI: 2.55–5.99). Larvae 4.18% (95% CI: 2.15–7.97) and females 4.08% (95% CI: 2.56–6.43) were the tick stage and sex with the highest infection rates. The presence of B. divergens, B. microti, and B. venatorum in tick vectors as revealed by the present study suggests possible risk of transmission of these pathogens to humans, especially occupationally exposed population. The control of tick vectors through chemical and biological methods as well as the use of repellants and appropriate clothing by occupationally exposed population are suggested to curtail the epidemiologic, economic, and public health threats associated with this emerging public health crisis.
Background
Babesia spp. are protozoan parasites of great medical and veterinary importance, especially in the northern Hemisphere. Ticks are known vectors of Babesia spp., although some Babesia- tick interactions have not been fully elucidated.
Methods
The present review was performed to investigate the specificity of Babesia -tick species interactions that have been identified using molecular techniques in studies conducted in the last 20 years under field conditions. We aimed to indicate the main vectors of important Babesia species based on published research papers ( n = 129) and molecular data derived from the GenBank database.
Results
Repeated observations of certain Babesia species in specific species and genera of ticks in numerous independent studies, carried out in different areas and years, have been considered epidemiological evidence of established Babesia -tick interactions. The best studied species of ticks are Ixodes ricinus , Dermacentor reticulatus and Ixodes scapularis (103 reports, i.e. 80% of total reports). Eco-epidemiological studies have confirmed a specific relationship between Babesia microti and Ixodes ricinus , Ixodes persulcatus , and Ixodes scapularis and also between Babesia canis and D. reticulatus . Additionally, four Babesia species (and one genotype), which have different deer species as reservoir hosts, displayed specificity to the I. ricinus complex. Eco-epidemiological studies do not support interactions between a high number of Babesia spp. and I. ricinus or D. reticulatus . Interestingly, pioneering studies on other species and genera of ticks have revealed the existence of likely new Babesia species, which need more scientific attention. Finally, we discuss the detection of Babesia spp. in feeding ticks and critically evaluate the data on the role of the latter as vectors.
Conclusions
Epidemiological data have confirmed the specificity of certain Babesia- tick vector interactions. The massive amount of data that has been thus far collected for the most common tick species needs to be complemented by more intensive studies on Babesia infections in underrepresented tick species.
Graphical abstract
Background
Wolbachia is an obligate intracellular maternally transmitted, gram-negative bacterium which forms a spectrum of endosymbiotic relationships from parasitism to obligatory mutualism in a wide range of arthropods and onchocercid nematodes, respectively. In arthropods Wolbachia produces reproductive manipulations such as male killing, feminization, parthenogenesis and cytoplasmic incompatibility for its propagation and provides an additional fitness benefit for the host to protect against pathogens, whilst in onchocercid nematodes, apart from the mutual metabolic dependence, this bacterium is involved in moulting, embryogenesis, growth and survival of the host.
Methods
This review details the molecular data of Wolbachia and its effect on host biology, immunity, ecology and evolution, reproduction, endosymbiont-based treatment and control strategies exploited for filariasis. Relevant peer-reviewed scientic papers available in various authenticated scientific data bases were considered while writing the review.
Conclusions
The information presented provides an overview on Wolbachia biology and its use in the control and/or treatment of vectors, onchocercid nematodes and viral diseases of medical and veterinary importance. This offers the development of new approaches for the control of a variety of vector-borne diseases.
Graphic Abstract
Babesiosis caused by the Babesia species is a parasitic tick-borne disease. It threatens many mammalian species and is transmitted through infected ixodid ticks. To date, the global occurrence and distribution are poorly understood in questing ticks. Therefore, we performed a meta-analysis to estimate the distribution of the pathogen. A deep search for four electronic databases of the published literature investigating the prevalence of Babesia spp. in questing ticks was undertaken and obtained data analyzed. Our results indicate that in 104 eligible studies dating from 1985 to 2020, altogether 137,364 ticks were screened with 3069 positives with an estimated global pooled prevalence estimates (PPE) of 2.10%. In total, 19 different Babesia species of both human and veterinary importance were detected in 23 tick species, with Babesia microti and Ixodes ricinus being the most widely reported Babesia and tick species, respectively. Regardless of species, adult ticks with 2.60% had the highest infection rates, while larvae had the least with 0.60%. Similarly, female ticks with 4.90% were infected compared to males with 3.80%. Nested-polymerase chain reaction (PCR) 2.80% had the highest prevalence among the molecular techniques employed. In conclusion, results obtained indicate that Babesia species are present in diverse questing tick species at a low prevalence, of which some are competent vectors.
Wolbachia symbionts, first observed in the 1920s, are now known to be present in about 30–70% of tested arthropod species, in about half of tested filarial nematodes (including the majority of human filarial nematodes), and some plant-parasitic nematodes. In arthropods, they are generally viewed as parasites while in nematodes they appear to be mutualists although this demarcation is not absolute. Their presence in arthropods generally leads to reproductive anomalies, while in nematodes, they are generally required for worm development and reproduction. In mosquitos, Wolbachia inhibit RNA viral infections, leading to populational reductions in human RNA virus pathogens, whereas in filarial nematodes, their requirement for worm fertility and survival has been channeled into their use as drug targets for filariasis control. While much more research on these ubiquitous symbionts is needed, they are viewed as playing significant roles in biological processes, ranging from arthropod speciation to human health.
The most important limiting factor to the productivity of livestock animals is the prevalence of ticks and the diseases transmitted by them. Ticks are hematophagous arthropods which may transmit various viral, bacterial, rickettsial and protozoal diseases to animals and humans. A number of plants are used in South African traditional ethnoveterinary medicine for the control of ticks, as well as symptoms relating to tick-borne diseases. The efficacy of ethnoveterinary plants and practices for preventing and treating ticks and tick-borne diseases needs to be fully investigated with a view to potential integration into primary animal healthcare.
Ticks are exclusive blood-feeding parasites that are of medical and veterinary importance. Ticks are also host for several maternally inherited symbiotic bacteria that are non-pathogenic bacteria and have potential roles in tick biology and the transmission of co-infecting pathogens. In order to gain a comprehensive view of these symbionts in ticks, we overviewed their incidence and biological importance within ticks based on available data. The symbionts in ticks are diverse, and their incidence and frequency vary across different tick species and different geographical populations of the same species. In some cases, symbionts of Coxiella, Francisella and Rickettsia genera may provide tick hosts essential nutrients absent from the exclusive food source of ticks and exhibit mutualistic relationships with their hosts. However, most symbionts are facultative and affect the biological phenotypes of their tick hosts through various ways. For some strains of Coxiella and Francisella, advanced genomic data and phylogenetic investigations have revealed their interactions with hosts and their evolutionary transitions of pathogenic and mutualistic forms. These findings are valuable for understanding tick-symbiont associations, and may help to develop new strategies to control ticks and tick-borne diseases.
Ixodes ricinus is undoubtedly the most well-known and studied European tick species.
Background
Despite great progress in studies on Wolbachia infection in insects, the knowledge about its relations with beetle species, populations and individuals, and the effects of bacteria on these hosts, is still unsatisfactory. In this review we summarize the current state of knowledge about Wolbachia occurrence and interactions with Coleopteran hosts.
Methods
An intensive search of the available literature resulted in the selection of 86 publications that describe the relevant details about Wolbachia presence among beetles. These publications were then examined with respect to the distribution and taxonomy of infected hosts and diversity of Wolbachia found in beetles. Sequences of Wolbachia genes ( 16S rDNA, ftsZ ) were used for the phylogenetic analyses.
Results
The collected publications revealed that Wolbachia has been confirmed in 204 beetle species and that the estimated average prevalence of this bacteria across beetle species is 38.3% and varies greatly across families and genera (0–88% infected members) and is much lower (c. 13%) in geographic studies. The majority of the examined and infected beetles were from Europe and East Asia. The most intensively studied have been two groups of herbivorous beetles: Curculionidae and Chrysomelidae. Coleoptera harbor Wolbachia belonging to three supergroups: F found in only three species, and A and B found in similar numbers of beetles (including some doubly infected); however the latter two were most prevalent in different families. A total of 59% of species with precise data were found to be totally infected. Single infections were found in 69% of species and others were doubly- or multiply-infected. Wolbachia caused numerous effects on its beetle hosts, including selective sweep with host mtDNA (found in 3% of species), cytoplasmic incompatibility (detected in c. 6% of beetles) and other effects related to reproduction or development (like male-killing, possible parthenogenesis or haplodiploidy induction, and egg development). Phylogenetic reconstructions for Wolbachia genes rejected cospeciation between these bacteria and Coleoptera, with minor exceptions found in some Hydraenidae, Curculionidae and Chrysomelidae. In contrast, horizontal transmission of bacteria has been suspected or proven in numerous cases (e.g., among beetles sharing habitats and/or host plants).
Discussion
The present knowledge about Wolbachia infection across beetle species and populations is very uneven. Even the basic data about infection status in species and frequency of infected species across genera and families is very superficial, as only c. 0.15% of all beetle species have been tested so far. Future studies on Wolbachia diversity in Coleoptera should still be based on the Multi-locus Sequence Typing system, and next-generation sequencing technologies will be important for uncovering Wolbachia relations with host evolution and ecology, as well as with other, co-occurring endosymbiotic bacteria.
Publications dedicated to studies of the hard ticks in urban landsapes cjver 68 countries and about 800 cities of the world. A detailed boibliography is provided.
To assess canine exposure to spotted fever group rickettsiae in the central provinces of Spain, ticks removed from dogs were studied by immunofluorescence (IF) staining. Twenty-eight out of 65 (43.0%) samples from ticks were positive. Sera from 58 dogs were also collected and the presence of antibodies to Rickettsia conorii studied. Thirty-four (58.6%) dogs presented significant titers by IF. Surveillance data from these provinces show the presence of Boutonneuse fever cases during recent years, evidence that dogs could serve as an indicator of rickettsial activity in these areas.
To characterize the clinical presentation and course, laboratory findings, and treatment outcome of 12 patients with human granulocytic ehrlichiosis.
The 12 patients were male, ranged in age from 29 to 91 years, and contracted their illness in Wisconsin or Minnesota.
Cases were recognized by the presence of intracytoplasmic inclusions (morulae) in peripheral neutrophils of patients presenting with temperature of 38.5 degrees C or higher, chills, severe headache, and myalgias. All patients had a complete blood cell count and blood chemistry profile. Blood smears were examined by light microscopy. All available paired serum samples were analyzed for presence of indirect fluorescent antibodies against Ehrlichia chaffeensis, Ehrlichia phagocytophila, and Ehrlichia equi. Blood samples from 12 patients were subjected to polymerase chain reaction analysis using primers specific for the E phagocytophila/E equi group, primers that include the agent identified in our patients, as well as E chaffeensis.
Varying combinations of leukopenia, anemia, and thrombocytopenia were found in all but one patient. All 12 patients demonstrated morulae in the cytoplasm of neutrophils, but not in mononuclear white blood cells. Serum assays failed to detect antibodies against E chaffeensis, but eight of 10 patients and seven of 10 patients tested had antibody titers of 1:80 or more for E phagocytophila and E equi, respectively. Polymerase chain reaction products obtained with primers for E phagocytophila, E equi, and the granulocytotropic Ehrlichia revealed that seven patients were infected with the same agent. The results of serological assays or polymerase chain reaction strongly suggest that all 12 patients were infected by E phagocytophila, E equi, or a closely related Ehrlichia species. Two of the 12 patients died. The other 10 patients improved rapidly with oral doxycycline treatment.
We believe that all 12 patients have been infected with a granulocytic Ehrlichia species, reflecting a recently described new disease entity. The infective organism appears to be closely related to E phagocytophila and E equi. The geographic domain of human granulocytic ehrlichiosis is currently unknown. This novel granulocytic Ehrlichia species is capable of causing fatal infections in humans. Early detection and treatment with tetracycline drugs appear to offer the best chance for complete recovery.
The 16S ribosomal DNAs (rDNAs) of two strains of Francisella tularensis and one strain of Francisella philomiragia were sequenced. On the basis of phylogenetic analysis data, the genus Francisella was placed in the gamma subclass of the Proteobacteria. The most closely related organism was the intracellular bacterium Wolbachia persica. The sequenced 16S rDNA molecules of the Francisella species exhibited very high levels of similarity (98.5 to 99.9%). Two variable regions, comprising 390 to 450 nucleotides of the 16S rDNA molecules of 17 additional Francisella strains, including members of the species F. tularensis and F. philomiragia, were also sequenced. At most, six nucleotide differences were observed among the sequences of the F. tularensis strains. The sequence of Francisella novicida was virtually identical to the sequences of the F. tularensis strains, thereby supporting the hypothesis that these organisms are members of the same species. On the basis of the observed differences, primer pairs were designed to distinguish strains by using the PCR at the genus, species, and subspecies levels. This permitted sensitive identification of strains belonging to the genus Francisella and discrimination of the species F. tularensis and F. philomiragia.
Six patients from northern Minnesota and Wisconsin with a febrile illness accompanied by granulocytic cytoplasmic morulae suggestive of ehrlichial infection were identified. Two patients died, and splenic granulocytes of one patient contained cytoplasmic vacuoles with organisms ultrastructurally characteristic of ehrlichiae. From one patient, a 1.5-kb DNA product was amplified by PCR with universal eubacterial primers of 16S rDNA. Analysis of the nucleotide sequence of the amplified product revealed 99.9 and 99.8% similarities with E. phagocytophila and E. equi, respectively, neither of which has previously been known to infect humans. From the variable regions of the determined sequence, a forward primer specific for three organisms (human granulocytic ehrlichia, E. phagocytophila, and E. equi) and a reverse primer for these ehrlichiae and E. platys were designed. By nested PCR with amplification by the universal primers and then reamplification with the specific primers described above, the expected 919-bp product was generated from the blood of the index patient and three additional patients. Blood from these four patients and two more patients with granulocytic morulae contained DNA which was amplified by nested PCR involving a combination of a universal primer and the human granulocytic ehrlichia-E. phagocytophila-E. equi-E. platys group-specific primer. This apparently vector-borne human granulocytic ehrlichia has only 92.5% 16S rDNA homology with E. chaffeensis. Nested PCR with group-specific primers did not amplify E. chaffeensis DNA, and E. chaffeensis-specific primers did not amplify DNAs of the human granulocytic ehrlichia. Thus, six patients were shown to be infected by an Ehrlichia species never previously reported to infect humans.
The role of white-tailed deer (Odocoileus virginianus) in the epidemiology of Ehrlichia chaffeensis and the agent of human granulocytic ehrlichiosis (HGE) is not fully understood, and diagnostic procedures may be complicated by the recent detection of 16S rDNA sequence from an Ehrlichia sp.-like organism in wild deer. A specific forward primer (DGA) and an Ehrlichia spp. reverse primer (GA1UR) were constructed to amplify this new, distinct Ehrlichia sp.-like 16S rDNA. The DGA primer, a forward primer specific for E. chaffeensis (DCH), and a forward primer specific for the E. phagocytophila genogroup (GE9f) were each used with GA1UR in nested polymerase chain reactions to amplify 16S rDNA sequences from control samples containing the deer Ehrlichia sp.-like organism, E. chaffeensis, or the HGE agent. Primer pairs DGA/GA1UR and DCH/GA1UR specifically amplified 16S rDNA sequences from the corresponding target organism, whereas GE9f/GA1UR amplified 16S rDNA sequence from both the HGE agent and the deer Ehrlichia sp.-like organism. With a nested PCR using DGA/GA1UR and DCH/GA1IUR on DNA extracted from white blood cells from 62 deer from 10 populations in four U.S. states, we observed a high prevalence (65%) of 16S rDNA sequences of the deer Ehrlichia sp.-like organism, and a low prevalence (5%) of the E. chaffeensis sequence. In this field survey, E. chaffeensis-reactive antibodies detected by indirect fluorescence assays were associated (P < 0.001) with PCR evidence of the deer Ehrlichia sp.-like organism, but not E. chaffeensis. Infestations of Amblyomma americanum also were associated (P < 0.001) with PCR evidence of the deer Ehrlichia sp.-like organism. The potential for serologic cross-reactions and non-specific PCR products arising from the deer Ehrlichia sp.-like organism should be considered when evaluating the role of deer and their ticks in the epidemiology of ehrlichial pathogens of humans.
Human granulocytic ehrlichiosis (HGE) was recently described in North America. It is caused by an Ehrlichia species closely related to Ehrlichia phagocytophila and Ehrlichia equi, recognized to infect mostly ruminants and horses, respectively. The vector in North America is the tick Ixodes scapularis, which is also the vector of the Lyme disease agent, Borrelia burgdorferi. Previous serologic studies in patients with a diagnosis of Lyme borreliosis indicate that HGE may exist in Europe. We report the first documented case of HGE in Europe. The diagnosis was established by seroconversion to E. equi and the HGE agent and by PCR with sequence analysis of the gene encoding the HGE agent 16S rRNA. Interestingly, the patient presented with a self-limited but moderately severe illness. Thus, European physicians need to be aware that HGE exists in Europe and that the diagnosis should be considered in febrile patients with tick bites in areas where Lyme disease is endemic.
The presence, internal distribution, and phylogenetic position of endosymbiotic bacteria from four species of specific-pathogen-free ticks were studied. These included the hard ticks Ixodes scapularis (the black-legged tick), Rhipicephalus sanguineus (the brown dog tick), and Haemaphysalis longicornis and the African soft tick Ornithodoros moubata. PCR assays for bacteria, using two sets of general primers for eubacterial 16S and 23S rRNA genes (rDNAs) and seven sets of specific primers for wolbachial, rickettsial, or Francisella genes, indicated that I. scapularis possessed symbiotic rickettsiae in the ovaries and that the other species harbored eubacteria in both the ovaries and Malpighian tubules. Phylogenetic analysis based on the sequence of 16S rDNA indicated that the symbiont of I. scapularis belonged to the alpha subgroup of proteobacteria and was closely related to the members of the genus Rickettsia. The other species had similar microorganisms in the ovaries and Malpighian tubules, which belonged to the gamma subgroup of proteobacteria, and formed a monophyletic group with the Q-fever pathogen, Coxiella burnetii. O. moubata harbored another symbiont, which formed a monophyletic group with Francisella tularensis and Wolbachia persica, the latter a symbiont previously isolated from Malpighian tubules of the soft tick Argas (Persicargas) arboreus. Thus, the symbionts of these four tick species were not related to the Wolbachia species found in insects. The two symbionts that live in the Malpighian tubules, one closely related to C. burnetii and the other closely related to F. tularensis, appear to be of ancient origin and be widely distributed in ticks.
To date, human granulocytic ehrlichiosis (HGE), the causative agent of which is likely transmitted by ticks in the Ixodes ricinus-Ixodes persulcatus complex, has not been diagnosed with certainty in patients outside the United States. The presence of a closely related vector tick, I. ricinus, as well as the occurrence of similar Ehrlichia spp. of veterinary importance, suggests that this disease is likely to be present in Europe. The aim of the present study was to compare the prevalence of antibodies against the HGE agent in sera collected from patients in groups at high risk for exposure to I. ricinus with that of a control population. Risk groups consisted of 150 forestry workers and 105 patients with an established diagnosis of Lyme disease. The control group was 103 healthy blood donors without a history of tick bites. We used a patient isolate of the HGE agent from Minnesota (J. L. Goodman, C. Nelson, B. Vitale, J. E. Madigan, J. S. Dumler, T. J. Kurtti, and U. G. Munderloh, N. Engl. J. Med. 334:209-215, 1996) propagated in HL60 cells as the source of antigen for a specific immunofluorescence assay (IFA). Elevated IFA titers (> or = 1:80) were present in 21 of 150 (14%) serum samples from forestry workers and in 12 of 105 (11.4%) serum samples from Lyme disease patients, but in only 2 of 103 (1.9%) serum samples from blood donors (P < or = 0.01 for either of the at-risk groups versus blood donors). The results of this study suggest that the HGE agent or a closely related organism exists in southern Germany and that seroconversion to it is common among groups exposed to Ixodes ticks. Final proof that HGE occurs in Germany will require the isolation of the causative agent from patients. HGE should be considered in the differential diagnosis of febrile illnesses in individuals exposed to Ixodes ticks in Europe as well as in North America.
A total of 1,523 adult Ixodes ricinus ticks were collected from regions where bovine ehrlichiosis is endemic and were examined for Ehrlichia phagocytophila via PCR. Of the ticks from cattle with ehrlichiosis, the ticks from healthy cattle, and the free-living ticks, 26.5% (18 of 68), 4.4% (35 of 802), and 0.8% (5 of 653), respectively, were positive.
In the present study further characterization of the amplified sequence of the citrate synthase gene of the spotted fever group Rickettsia isolated from Ixodes ricinus ticks in Sweden showed that it has 100% homology with the deposited sequence of the citrate synthase gene of Rickettsia helvetica. The restriction fragment length polymorphism (RFLP) pattern of an amplified 382-bp product of the citrate synthase sequence, defined by primers RpCS877 and RpCS1258, yielded fragments for our isolate that could be visualized as a double band that migrated at approximately 44 bp, another double band at 85 bp, and a single band at nearly 120 bp after digestion with the restriction enzyme AluI. When calculating a theoretical PCR-RFLP pattern of the sequence of the citrate synthase gene of R. helvetica from the known positions where the AluI enzyme cuts, we arrived at the same pattern that was obtained for our isolate, a pattern distinctly different from the previously published PCR-RFLP pattern for R. helvetica. Investigation of 125 living I. ricinus ticks showed a higher prevalence of rickettsial DNA in these ticks than we had found in an earlier study. Rickettsial DNA was detected by amplification of the 16S rRNA gene, for which a seminested primer system consisting of two oligonucleotide primer pairs was used. Of the 125 ticks, some were pooled, giving a total of 82 tick samples, of which 20 were found to be positive for the rickettsial DNA gene investigated. When considering the fact that some of the positive samples were pooled, the minimum possible prevalence in these ticks was 20 of 125 (16%) and the maximum possible prevalence was 46 of 125 (36.8%). These prevalence estimates conform to those of other studies of spotted fever group rickettsiae in hard ticks in Europe.
A total of 1,667 Ixodes ricinus ticks were collected from five regions in Switzerland where there have been sporadic occurrences of granulocytic ehrlichiosis in dogs and horses. The ticks were examined for rickettsiae of the Ehrlichia phagocytophila group via nested PCR. Twenty-one ticks (1.3%) were positive; 3 (0.5%) were nymphs, 6 (1.3%) were adult males, and 12 (1.9%) were adult females. The number of positive ticks varied with the stage of development and with the geographical origin. Nucleotide sequencing of the isolated PCR products identified these products as part of the 16S rRNA gene of Ehrlichia. In addition, these products had 100% homology with the agent of human granulocytic ehrlichiosis. The occurrence of this agent in I. ricinus in Switzerland presents a potential danger of transmission of granulocytic ehrlichiosis to dogs, horses, and humans.
A total of 287 adult Ixodes ricinus ticks, collected in two regions of southern Germany (Frankonia and Baden-Württemberg) where Borrelia burgdorferi infections are known to be endemic, were examined for the presence of 16S ribosomal DNA specific for the Ehrlichia phagocytophila genogroup, E. chaffeensis, E. canis, and B. burgdorferi by nested PCR. Totals of 2.2% (6 of 275) and 21.8% (65 of 275) of the ticks were positive for the E. phagocytophila genogroup and B. burgdorferi, respectively. Two ticks (0.7%) were coinfected with both bacteria. Of 12 engorged I. ricinus ticks collected from two deer, 8 (67%) were positive for the E. phagocytophila genogroup and one (8%) was positive for B. burgdorferi. There was no evidence of infection with E. canis or E. chaffeensis in the investigated tick population. The nucleotide sequences of the 546-bp Ehrlichia PCR products differed at one or two positions from the original sequence of the human granulocytic ehrlichiosis (HGE) agent (S.-M. Chen, J. S. Dumler, J. S. Bakken, and D. H. Walker, J. Clin. Microbiol. 32:589-595, 1994). Three groups of sequence variants were detected; two of these were known to occur in other areas in Europe or the United States, whereas one has not been reported before. Thus, in the German I. ricinus tick population closely related granulocytic ehrlichiae are prevalent, which might represent variants of E. phagocytophila or the HGE agent.
The presence of granulocytic ehrlichiae was demonstrated by PCR in Ixodes ricinus ticks and wild small mammals in Switzerland in two areas of endemicity for bovine ehrlichiosis. Six ticks (three females and three nymphs) (1.4%) of 417 I. ricinus ticks collected by flagging vegetation contained ehrlichial DNA. A total of 201 small mammals from five species, wood mouse (Apodemus sylvaticus), yellow-necked mouse (Apodemus flavicollis), earth vole (Pitymys subterraneus), bank vole (Clethrionomys glareolus), and common shrew (Sorex araneus), were trapped. The analysis of I. ricinus ticks [corrected] collected on 116 small mammals showed that nine C. glareolus voles and two A. sylvaticus mice hosted infected tick larvae. In these rodents, granulocytic ehrlichia infection was also detected in blood, spleen, liver, and ear samples. Further examinations of 190 small mammals without ticks or with noninfected ticks showed the presence of ehrlichial DNA in spleen and other tissues from six additional C. glareolus, three A. flavicollis, and one S. araneus mammals. This study suggests that A. sylvaticus, A. flavicollis, S. araneus, and particularly C. glareolus are likely to be natural reservoirs for granulocytic ehrlichiae. Partial 16S rRNA gene sequences of granulocytic ehrlichiae from ticks and rodents showed a high degree of homology (99 to 100%) with granulocytic ehrlichiae isolated from humans. In contrast, groESL heat shock operon sequence analysis showed a strong divergence (approximately 5%) between the sequences in samples derived from rodents and those derived from samples from questing ticks or from other published ehrlichia sequences. Dual infections with granulocytic ehrlichia and Borrelia burgdorferi were found in ticks and small mammals.
Babesiosis is an emerging, tick-transmitted, zoonotic disease caused by hematotropic parasites of the genus Babesia. Babesial parasites (and those of the closely related genus Theileria) are some of the most ubiquitous and widespread blood parasites in the world, second only to the trypanosomes, and consequently have considerable worldwide economic, medical, and veterinary impact. The parasites are intraerythrocytic and are commonly called piroplasms due to the pear-shaped forms found within infected red blood cells. The piroplasms are transmitted by ixodid ticks and are capable of infecting a wide variety of vertebrate hosts which are competent in maintaining the transmission cycle. Studies involving animal hosts other than humans have contributed significantly to our understanding of the disease process, including possible pathogenic mechanisms of the parasite and immunological responses of the host. To date, there are several species of Babesia that can infect humans, Babesia microti being the most prevalent. Infections with Babesia species generally follow regional distributions; cases in the United States are caused primarily by B. microti, whereas cases in Europe are usually caused by Babesia divergens. The spectrum of disease manifestation is broad, ranging from a silent infection to a fulminant, malaria-like disease, resulting in severe hemolysis and occasionally in death. Recent advances have resulted in the development of several diagnostic tests which have increased the level of sensitivity in detection, thereby facilitating diagnosis, expediting appropriate patient management, and resulting in a more accurate epidemiological description.
A 37-year-old man living in eastern France seroconverted to Rickettsia helvetica in August 1997, 4 weeks after the onset of an unexplained febrile illness. Results of a serosurvey of forest workers from the area where the patient lived showed a 9.2% seroprevalence against R. helvetica. This organism may pose a threat for populations exposed to Ixodes ricinus ticks.
A total of 6071 Ixodes ricinus ticks were collected on Swiss Army training grounds in five regions of Switzerland. The aim of the survey was to assess the prevalence of ticks infected with the human pathogens Francisella tularensis, members of the Ehrlichia phagocytophila genogroup, Borrelia burgdorferi sensu lato, and the European tick-borne encephalitis virus. TaqMan PCR (PE Biosystems, USA) and TaqMan RT-PCR (PE Biosystems) analyses were performed on DNA and RNA extracted from pools of ten ticks grouped by gender. Here, for the first time, it is shown that ticks may harbor Francisella tularensis in Switzerland, at a rate of 0.12%. Furthermore, 26.54% of the ticks investigated harbored Borrelia burgdorferi sensu lato, 1.18% harbored members of the Ehrlichia phagocytophila genogroup, and 0.32% harbored the European tick-borne encephalitis virus. A new instrumentation was applied in this study to carry out and analyze more than 2300 PCR reactions in only 5 days. Furthermore, the results reveal that people working in outdoor areas, including army personnel on certain training grounds contaminated with ticks containing tick-borne pathogens, are at risk for different tick-borne diseases.
Human babesiosis is an important emerging tick-borne disease. Babesia divergens, a parasite of cattle, has been implicated as the most common agent of human babesiosis in Europe, causing severe disease in splenectomized individuals. In the US, Babesia microti, a babesial parasite of small mammals, has been the cause of over 300 cases of human babesiosis since 1969, resulting in mild to severe disease, even in non-splenectomised patients. Changing ecology has contributed greatly to the increase and expansion of human babesiosis in the US. A relatively recently described babesial parasite, the WA1-type, has been shown to be the causative agent in seven human cases in the western US. This parasite is closely related to babesial parasites isolated from large wild ungulates in California. Like B. microti, WA1-type parasites cause mild to severe disease and the immunopathogenesis of these parasites is distinctly different from each other in experimental infections of hamsters and mice. A B. divergens-like parasite was also identified as the cause of a fatal human babesiosis case in Missouri. Isolated cases of human babesisosis have been described in Africa and Mexico, but the causative parasites were not well characterized. Standard diagnostic techniques for human infection, such as examination of Giemsa-stained thin blood smears and serology, have been complemented with molecular techniques, such as PCR. Current treatment for babesiosis is focused on a regimen of clindamycin and quinine, although new drugs have shown promise. Prevention of infection relies on self-monitoring for the presence of ticks and, in some locations, targeted application of pesticides to decrease tick abundance. Identification of human infection with Babesia spp. will probably increase as physicians and the public become more aware of the disease, as people live and recreate in rural tick-infested areas, and as the numbers of immunocompromised individuals increase.
Questing Ixodes ricinus (Acari: Ixodidae) adult and nymphal ticks collected in various parts of Slovenia were tested for the presence of babesial
parasites with a PCR assay based on the nuclear small subunit rRNA gene (nss-ribosomal DNA [rDNA]). Thirteen of 135 ticks
were found to contain babesial DNA. Sequence determination and analysis of amplified portions of nss-rDNA revealed their identity
with Babesia microti and a high degree of homology withBabesia odocoilei and Babesia divergens. The results of this study represent the first genetic evidence ofB. microti and B. divergens-like parasites in I. ricinus ticks in Europe.
Babesia microti and B. divergens, the etiological agents of human babesiosis, are transmitted by the bite of Ixodes ricinus. The purpose of this study was differentiation of those two species in ticks collected in urban woods in the city Szczecin (north-western Poland). The prevalence of the DNA of Babesia were investigated by PCR amplification with primers to the fragment from a gene encoding the nuclear small-subunit ribosomal RNA (SS-rDNA). We examined a total of 533 specimens of Ixodes ricinus. The mean infection rate was 16.3%. Our results indicate that a B. microti and B. divergens--specific PCR test may provide a sensitive tool also for the laboratory diagnosis of human babesiosis.
The genera Anaplasma, Ehrlichia, Cowdria, Neorickettsia and Wolbachia encompass a group of obligate intracellular bacteria that reside in vacuoles of eukaryotic cells and were previously placed in taxa based upon morphological, ecological, epidemiological and clinical characteristics. Recent genetic analyses of 16S rRNA genes, groESL and surface protein genes have indicated that the existing taxa designations are flawed. All 16S rRNA gene and groESL sequences deposited in GenBank prior to 2000 and selected sequences deposited thereafter were aligned and phylogenetic trees and bootstrap values were calculated using the neighbour-joining method and compared with trees generated with maximum-probability, maximum-likelihood, majority-rule consensus and parsimony methods. Supported by bootstrap probabilities of at least 54%, 16S rRNA gene comparisons consistently clustered to yield four distinct clades characterized roughly as Anaplasma (including the Ehrlichia phagocytophila group, Ehrlichia platys and Ehrlichia bovis) with a minimum of 96.1% similarity, Ehrlichia (including Cowdria ruminantium) with a minimum of 97.7% similarity, Wolbachia with a minimum of 95.6% similarity and Neorickettsia (including Ehrlichia sennetsu and Ehrlichia risticii) with a minimum of 94.9% similarity. Maximum similarity between clades ranged from 87.1 to 94.9%. Insufficient differences existed among E. phagocytophila, Ehrlichia equi and the human granulocytic ehrlichiosis (HGE) agent to support separate species designations, and this group was at least 98.2% similar to any Anaplasma species. These 16S rRNA gene analyses are strongly supported by similar groESL clades, as well as biological and antigenic characteristics. It is proposed that all members of the tribes Ehrlichieae and Wolbachieae be transferred to the family Anaplasmataceae and that the tribe structure of the family Rickettsiaceae be eliminated. The genus Anaplasma should be emended to include Anaplasma (Ehrlichia) phagocytophila comb. nov. (which also encompasses the former E. equi and the HGE agent), Anaplasma (Ehrlichia) bovis comb. nov. and Anaplasma (Ehrlichia) platys comb. nov., the genus Ehrlichia should be emended to include Ehrlichia (Cowdria) ruminantium comb. nov. and the genus Neorickettsia should be emended to include Neorickettsia (Ehrlichia) risticii comb. nov. and Neorickettsia (Ehrlichia) sennetsu comb. nov.
Parasitic filarial nematodes infect more than 200 million individuals worldwide, causing debilitating inflammatory diseases
such as river blindness and lymphatic filariasis. Using a murine model for river blindness in which soluble extracts of filarial
nematodes were injected into the corneal stroma, we demonstrated that the predominant inflammatory response in the cornea
was due to species of endosymbiotic Wolbachia bacteria. In addition, the inflammatory response induced by these bacteria was dependent on expression of functional Toll-like
receptor 4 (TLR4) on host cells.
The tick Ixodes ricinus may carry microorganisms which cause serious human and animal diseases, i.a., the Lyme disease (borreliosis), caused by the spirochaete Borrelia burgdorferi sensu lato and babesiosis, induced by the protozoan Babesia microti. Both microbe species may co-occur in the same and other species of the genus tick and produce a mixed infection in humans and animals. The major objective of the study was to identify DNA of B. burgdorferi and B. microti in the I. ricinus ticks collected in spring and autumn 1999 from 6 sites in north-western Poland. The microbial DNA was identified with polymerase chain reaction (PCR). The marker used to detect the B. burgdorferi s.l. DNA was a fragment of the fla gene encoding the protein flagellin, while the B. microti DNA was detected with a fragment of the gene encoding 16S rRNA. A total of 550, 1,160, and 385 tick adults, nymphs, and larvae, respectively, were examined. Among the 155 (7.4%) B. burgdorferi- infected ticks and the 130 (6.2%) infected with B. microti, mixed infection was detected in 0.6% of individuals. The prevalence of coinfection differed between the tick developmental stages. Coinfection was most prevalent (3.1%) in females, males and nymphs being less affected (0.4 and 0.2%, respectively). No coinfection was revealed in the tick larvae. The study described was the first of its kind to be conducted in the former District of Szczecin. For the phenomenon of microbial co-occurrence and related mixed infections to be properly evaluated, the research will be continued.
Objective.
—To characterize the clinical presentation and course, laboratory findings, and treatment outcome of 12 patients with human granulocytic ehrlichiosis.
Setting.
—The 12 patients were male, ranged in age from 29 to 91 years, and contracted their illness in Wisconsin or Minnesota.
Methods.
—Cases were recognized by the presence of intracytoplasmic inclusions (morulae) in peripheral neutrophils of patients presenting with temperature of 38.5°C or higher, chills, severe headache, and myalgias. All patients had a complete blood cell count and blood chemistry profile. Blood smears were examined by light microscopy. All available paired serum samples were analyzed for presence of indirect fluorescent antibodies against Ehrlichia chaffeensis, Ehrlichia phagocytophila, and Ehrlichia equi. Blood samples from 12 patients were subjected to polymerase chain reaction analysis using primers specific for the E phagocytophila/E equi group, primers that include the agent identified in our patients, as well as E chaffeensis.
Results.
—Varying combinations of leukopenia, anemia, and thrombocytopenia were found in all but one patient. All 12 patients demonstrated morulae in the cytoplasm of neutrophils, but not in mononuclear white blood cells. Serum assays failed to detect antibodies against E chaffeensis, but eight of 10 patients and seven of 10 patients tested had antibody titers of 1:80 or more for E phagocytophila and E equi, respectively. Polymerase chain reaction products obtained with primers for E phagocytophila, E equi, and the granulocytotropic Ehrlichia revealed that seven patients were infected with the same agent. The results of serological assays or polymerase chain reaction strongly suggest that all 12 patients were infected by E phagocytophila, E equi, or a closely related Ehrlichia species. Two of the 12 patients died. The other 10 patients improved rapidly with oral doxycycline treatment.
Conclusions.
—We believe that all 12 patients have been infected with a granulocytic Ehrlichia species, reflecting a recently described new disease entity. The infective organism appears to be closely related to E phagocytophila and E equi. The geographic domain of human granulocytic ehrlichiosis is currently unknown. This novel granulocytic Ehrlichia species is capable of causing fatal infections in humans. Early detection and treatment with tetracycline drugs appear to offer the best chance for complete recovery.(JAMA. 1994;272:212-218)
To the Editor: Human granulocytic ehrlichiosis was first reported in the United States in 1994.1 Over the past five years at least several hundred cases have been reported, mostly in the upper Midwest and Northeast, regions where other diseases transmitted by Ixodes scapularis ticks, such as Lyme disease and babesiosis, are common. Four cases of human granulocytic ehrlichiosis have also recently been documented in Slovenia.2 We describe a case of human granulocytic ehrlichiosis in western Europe. In September 1998, a 58-year-old Dutch man presented with a seven-day history of fever, chills, and diarrhea. He often camped in Gelderland, a region . . .
We studied the prevalence of rickettsia-like organisms infection in different tick species (3154 adults) collected in several areas of the Ebro valley (Spain). The Gimenez stain showed a prevalence of rickettsia-like organisms in 38.6% of the studied ticks. Using the immunofluorescence assay, only two species, Rhipicephalus sanguineus (16.4%) and R. pusillus (19.9%) have shown organisms compatible with spotted fever group rickettsiae.
A tick/rickettsial survey in various parts of Switzerland revealed the presence of a new, hitherto undescribed spotted fever group rickettsia ("Swiss agent") in up to 11.7% of I. ricinus collected off vegetation. Infection in ticks was found to be generalized with rickettsiae developing intracellularly and occasionally also intranuclearly. As a result of massive growth in ovarial tissues, including the germinative cells, the rate of transovarial and filial infection was 100%. The "Swiss agent" appears to be nonpathogenic for guinea pigs, domestic rabbits, and Swiss mice, but in male meadow voles (Microtus pennsylvanicus) it produces a microscopically detectable infection in the tunica vaginalis. The rickettsia grows well in tissue culture systems including chick embryo fibroblast, Vero, and vole tissue cells, when inoculated via yolk sac into 5-day-old hens' eggs, it kills 100% of the embryos after 5 to 7 days. Antigenic relatedness of the "Swiss agent" to rickettsiae of the spotted fever group was indicated by indirect and direct fluorescent antibody staining. Preliminary serologic typing by microimmunofluorescence and by microagglutination indicated that the "Swiss agent" differs from all prototype strains of spotted fever group rickettsiae studied so far.
Procedures utilizing Chelex 100 chelating resin have been developed for extracting DNA from forensic-type samples for use with the PCR. The procedures are simple, rapid, involve no organic solvents and do not require multiple tube transfers for most types of samples. The extraction of DNA from semen and very small bloodstains using Chelex 100 is as efficient or more efficient than using proteinase K and phenol-chloroform extraction. DNA extracted from bloodstains seems less prone to contain PCR inhibitors when prepared by this method. The Chelex method has been used with amplification and typing at the HLA DQ alpha locus to obtain the DQ alpha genotypes of many different types of samples, including whole blood, bloodstains, seminal stains, buccal swabs, hair and post-coital samples. The results of a concordance study are presented in which the DQ alpha genotypes of 84 samples prepared using Chelex or using conventional phenol-chloroform extraction are compared. The genotypes obtained using the two different extraction methods were identical for all samples tested.
Wolbachia-like symbiotes in the Rocky Mountain wood tick, Dermacentor andersoni, were isolated repeatedly by injection of ovarial tissues into 5-day-old chick embryos. In Giemsa-stained smears of infected embryo tissues, the organisms appeared as blueish or pinkstained coccal bodies indistinguishable from those seen in the ovaries of ticks, where they are located in the luminal epithelium and funicle cells, as well as in oocytes.Electron microscopy revealed that these symbiotes are highly pleomorphic and vary in size from 0.6 to 3.4 μm in diameter. Their fine structure in tissue cells is differentiated into a granular, cortical region, which contains densely stained ribosomes, and a medullary region consisting of a diffuse reticulum partially or completely devoid of granular material or ribosomes. Multiplication is by binary fission. Each organism is delimited by a distinct plasmalemma; a cell wall as in bacterial and rickettsial agents was not observed in organisms from ovarial tissues.Symbiotes cultivated in chick embryos and then injected intracoelomically into adult D. andersoni, developed rapidly and produced massive infestations in hemocytes, hypodermal tissues, salivary glands, and in connective tissues surrounding midgut, Malpighian tubules, and ovary. In hypodermal tissue, organisms with a distinct bilayered cell envelope were occasionally detected. The massive invasion of tissues by injected symbiotes invariably proved fatal for ticks.Results of complement-fixation tests and of fluorescent antibody staining indicated that symbiotes in D. andersoni are closely related to Wolbachia persica, previously isolated from Argas arboreus.
When 155 ticks collected in different regions of Switzerland were tested by the hemolymph test, 10.3% were found to contain spotted fever group rickettsiae. Six rickettsial isolates were made from Dermacentor marginatus ticks and three were made from Ixodes ricinus ticks. The polymerase chain reaction followed by restriction fragment length polymorphism analysis showed that the Dermacentor ticks were infected with Rickettsia length polymorphism analysis showed that the Dermacentor ticks were infected with Rickettsia slovaca and the Ixodes ticks were infected with a spotted fever group rickettsia. Microimmunofluorescence serologic type, sodium dodecyl sulfate-polyacrylamide gel electrophoresis of proteins, and Western blot assay with polyclonal mouse antisera confirmed the results and determined that the Ixodes were infected with R. helvetica, the only previously described Swiss rickettsia. However, an additional new strain that could not be isolated was detected in one I. ricinus by hemolymph test and provisionally characterized by enzymatic restriction of its amplified DNA.
The term rickettsiae initially encompassed all intracellular bacteria. Early rickettsial taxonomy was based on a comparison of a few phenotypic characteristics and recently, molecular studies brought new bases for rickettsial taxonomy. All rickettsial species studied so far belong to the alpha and gamma groups of the Proteobacteria. Ehrlichiae complex groups Cowdria ruminantium, Anaplasma marginale and Wolbachia pipientis and the related parthenogenesis and cytoplasmic incompatibility bacteria, whereas Rochalimaea species group with Bartonella bacilliformis. Rickettsia tsutsugamushi may form an independent lineage, whereas molecular data allow to regroup serologically defined typhus and spotted fever group rickettsiae. The true scale of Rickettsia and Coxiella genera remain to be determined.
We report the results of a comparison of several epidemiologic and ecologic parameters affecting the incidence and seroprevalence of Mediterranean spotted fever (MSF) in northern, central, and southeastern Marseille, an area endemic for this disease. In northern Marseille, the incidence of hospitalized patients with MSF was 24.2/100,000 persons compared with 9.8/100,000 and 8.8/100,000 for the central and southeastern regions, respectively. The seroprevalence in sera from blood donors, determined by microimmunofluorescence and confirmed by Western blot assays, was higher in the northern region than in the other two areas (6.7% versus 3.6% and 2.4%, respectively). This higher prevalence of MSF in the northern part of the city may be related to a greater tick exposure due to a higher number of dogs (32.6/100 inhabitants versus 28.4/100 and 27.2/100 in the central and southeastern regions, respectively) and a higher rate of infection of dogs in the northern region (51.4% versus 43.5% and 39.9%, respectively). The ratio of spotted fever group rickettsia-infected ticks was similar in both the northern and southeastern areas (14.8% and 13.4% respectively), but lower in the central area of the city (8.9%), leading to a higher risk of having MSF after a tick bite in the northern and southeastern parts of Marseille.
The first demonstrated case of human babesiosis in the world was reported in Europe, in 1957. Since then, a further 28 babesial infections in man have been reported in Europe. Most (83%) of the infections were in asplenic individuals and most (76%) were with Babesia divergens, a cattle parasite. Parasitaemias varied from 1%-80% of red blood cells. The usual clinical manifestations of severe B. divergens infection were severe intravascular haemolysis with haemoglobinuria. The most efficient treatment consisted of a massive blood-exchange transfusion, followed immediately by chemotherapy with clindamycin. Hundreds of cases of human infection with Babesia spp. have been reported in the U.S.A. Most cases were infected by ticks carrying the rodent parasite B. microti, but other emerging. Babesia spp. (currently known as WA1, CA1, and MO1) are increasingly involved. Several cases were the result of blood transfusion. In terms of clinical manifestations, human infections with B. microti varied widely, from asymptomatic infection to a severe, rapidly fatal disease. Parasitaemia ranged between <1% and 85%. The splenectomized, the elderly, the immunocompromised and HIV-infected patients were predisposed to severe infection. Infection with B. microti often remained subclinical or asymptomatic and were only detected through serological surveys. The currently recommended treatment of symptomatic cases is quinine plus clindamycin. A few other cases of human babesial infection have been described in China, Egypt, Mexico, South Africa and Taiwan.
To contribute to the discussion of whether or not human granulocytic ehrlichiosis (HGE) occurs in midwestern Germany, sera from individuals with different risk categories for tick exposure were retrospectively examined by means of an immunofluorescence assay. The seroreprevalence for the HGE agent accounted for 5.5% of the 270 patients tested. Specific antibodies were detected more often in patients with early Lyme infection than in patients with stage III disease or in asymptomatic individuals seropositive for Lyme disease. Investigation of 50 patients with an active or recent syphilis infection revealed no cross-reactivity between Treponema pallidum antibodies and the HGE agent. The prevalence of HGE antibodies (13.1%) among 76 Lyme borreliosis patients from this urban area was significantly higher (P < 0.05) than that in the control groups (2.6%). The findings indicate that concomitant or serial infections with Borrelia burgdorferi and the HGE agent or closely related organisms may be a common occurrence in tick-exposed patients from Germany.
Human granulocytic Ehrlichiosis (HGE) is a newly emerging acute febrile illness which is likely transmitted by ticks of the Ixodes ricinus/I. persulcatus complex. First seroepidemiological surveys on the prevalence of HGE antibodies, detection of DNA of granulocytotropic Ehrlichiae in I. ricinus and one case of HGE from Slovenia confirmed by serology and PCR (polymerase chain reaction) suggest that HGE might exist all over Europe. The purpose of the present study was a) to determine the prevalence of antibodies against the HGE agent in sera collected from persons at high risk for exposure to I. ricinus with that of a control population and b) to determine the prevalence of granulocytic Ehrlichiae in I. ricinus ticks from Southern Germany. We studied sera from 150 forestry workers and 105 patients with an established diagnosis of Lyme disease as tick-exposed populations. Sera from 103 healthy blood donors without a history of known tick bites served as controls. A significantly higher prevalence of HGE antibodies (P < or = 0.01) was present among patients with Lyme borreliosis (12 of 105 were positive; 11.4%) and forestry workers (21 of 150 were positive; 14%) compared to blood donors (2 of 103 were positive; 1.9%). Furthermore, 510 adult and nymphal I. ricinus were investigated by PCR for the presence of granulocytic Ehrlichiae with primers specific for the E. phagocytophila group. In eight (1.6%) of the investigated ticks the expected amplification product was detectable, indicating a low prevalence of infected ticks especially when compared with B. burgdorferi. The presented data strongly suggests that the HGE agent or a closely related organism exists in Southern Germany and therefore HGE should be considered in the differential diagnosis of febrile illnesses. However, final evidence can be provided only after isolation of the organism from patients.
A total of 305 Ixodes ricinus ticks (243 nymphs and 62 adults) were collected from three different regions of Thuringia in Middle Germany which are known to be endemic for Borrelia burgdorferi. Our aim was to investigate the carrier rate of ticks for granulocytic Ehrlichia species. The presence of ehrlichial 16S ribosomal DNA was investigated by polymerase chain reaction. Using primers specific for the Ehrlichia phagocytophila group PCR fragments of 151 bp and 943 bp, respectively, were produced in positive samples. Adult ticks showed a significantly higher infection rate (4/62; 6.5%) compared to nymphs (3/243; 1.2%). Prevalence rates varied between 0 and 3.8% regarding the different areas under investigation. The nucleotide sequences showed high similarity (between 97.5% and 99% identity) to the known sequences of the three E. phagocytophila group members HGE agent, E. phagocytophila and Ehrlichia equi. The sequence data did not allow a final classification to a particular member of this group.
Presently known tick-borne diseases in Germany include Lyme borreliosis, tick-borne encephalitis (TBE-virus, western subtype), Q-fever, babesiosis and presumably ehrlichiosis. Blood samples of 4,368 forestry workers in the State of Baden-Wuerttemberg (B-W), southwestern Germany, were tested for the presence of antibodies against Borrelia burgdorferi sensu lato, TBE-virus and Ehrlichia spp. (genogroup E. phagocytophila). Furthermore 12,327 ticks (Ixodes ricinus) collected in various areas of B-W were analysed by PCR and genotyping for the prevalence of pathogen RNA and DNA. The human seroprevalence rates of antibodies to B. burgdorferi sensu lato ranged from 18 % to 52 %, for TBE-virus from 0 % to 43 % and for Ehrlichia spp. from 5 % to 16 % in various counties of the State. The foci of B. burgdorferi and TBE-virus as indicated by antibody prevalence in humans are only partly overlapping with each other. The highest rates of TBE-virus antibodies are in concordance with available clinical data. However antibody prevalence up to 27 % in areas with no reports of clinical cases was found, suggesting that TBE occurs throughout the State of B-W, The prevalence of Ehrlichia spp. antibodies suggests that ehrlichiosis plays a role as a tick-borne disease in Germany, but as long as no clinical data are available, this will remain unclear.
Piroplasmosis in man
- Skrabalo
Skrabalo, Z., DeaniviS, Z.: Piroplasmosis in man. Docum. Med. Geogr. Trop. 9, 11-16 (1957).
Steuern Bakterien die Evolution der Insekten? Spektrum der Wissenschaft
- L D Hurst
- J P Randerson
Hurst, L.D., Randerson, J.P.: Steuern Bakterien die Evolution der Insekten? Spektrum der Wissenschaft, Oktober 56-60 (2002).
- M J Homer
- I Aguilar-Delfin
- S R Krause
- P J Persing
Homer, M. J., Aguilar-Delfin, I., Telford 3 rd, S. R.,
Krause, P. J., Persing, D. H.: Babesiosis. Clin. Microbiol. Rev. 13, 451 ± 469 (2000).
Prevalence of granulocytic ehrlichiae in Ixodes ricinus ticks in central Germany (Thuringia) detected by PCR and sequencing of a 16S ribosomal DNA fragment
- Hildebrandt
Steuern Bakterien die Evolution der Insekten?
- Hurst