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Nosema ceranae in European honey bees (Apis mellifera)

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Abstract

Nosema ceranae is a microsporidian parasite described from the Asian honey bee, Apis cerana. The parasite is cross-infective with the European honey bee, Apis mellifera. It is not known when or where N. ceranae first infected European bees, but N. ceranae has probably been infecting European bees for at least two decades. N. ceranae appears to be replacing Nosema apis, at least in some populations of European honey bees. This replacement is an enigma because the spores of the new parasite are less durable than those of N. apis. Virulence data at both the individual bee and at the colony level are conflicting possibly because the impact of this parasite differs in different environments. The recent advancements in N. ceranae genetics, with a draft assembly of the N. ceranae genome available, are discussed and the need for increased research on the impacts of this parasite on European honey bees is emphasized.

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... First described in the Asian honey bee Apis cerana [1], the microsporidium Vairimorpha (Nosema) ceranae became an emergent and highly virulent pathogen in colonies of European honey bees A. mellifera around the world [2][3][4][5]. The infection caused by V. ceranae, nosemosis type C, leads to a decrease in adult density and honey production and is implicated in colony losses, at least in southern European countries [5,6]. ...
... Thus, isolation of parasite spores from infected bees in temperate countries is most profitable in early spring [17]. (2) The insect may sting the personnel during experimental manipulations. (3) In contrast to the generalized microsporidian infection of the inner tissues of lepidopteran and orthopteran insects, V. ceranae growth is only observed in the epithelium of the bee midgut, which drastically reduces the spore yield from one insect. ...
... One of the ways to solve these problems is to isolate large amounts of parasite spores from infected insects in early spring and freeze them for consequent experiments [2,17]. Although the most efficient protocol for freezing V. ceranae spores was recommended among several techniques considered, their infectivity decreases by an order of magnitude after six months of storage. ...
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Nosemosis type C is a dangerous and widespread disease of the adult European honey bee Apis mellifera and is caused by the spore-forming intracellular parasite Vairimorpha (Nosema) ceranae. The search for new ways of therapy for this disease is complicated due to the seasonal availability of V. ceranae-infected insects as well as the lack of a developed system for the pathogen’s cultivation. By carrying out trials which used different infectious dosages of the parasite, spore storage protocols, host age, and incubation temperatures, we present a simple, safe, and efficient method of V. ceranae propagation in artificially infected worker bees in the laboratory. The method is based on feeding the groups of adult worker bees with microsporidian spores and insect maintenance in plastic bottles at 33 °C. The source of the spores originated from the cadavers of infected insects from the previous round of cultivation, in which the infective spores persist for up to six months. An analysis of five independent cultivation rounds involving more than 2500 bees showed that the proposed protocol exploiting the dosage of one million spores per bee yielded over 60 million V. ceranae spores per bee, and most of the spore samples can be isolated from living insects.
... Vairimorpha apis and Vairimorpha ceranae are the two well-known species for honeybees (Chen et al. 2009). Recently, a new Vairimorpha-like microsporidian, Vairimorpha neumanni, has been identified only in Uganda honeybees; however, its distribution and effects on the host bee remain unknown (Cilia et al. 2019).The former two species are specific to adult bees and cause nosemosis by disrupting the digestive tract of the bees-worker, nurse, drone, and queen Fries 2010;Papini et al. 2017). Nosemosis is one of the most important and serious threats to beekeeping worldwide (Porrini et al. 2020) and causes severe economic losses through negative effects on the biology, physiology, biochemistry, immunology, and inherent behaviors of the population in a colony (Botias et al. 2013;Papini et al. 2017). ...
... Although it still remains unknown when and how this microsporidian pathogen has introduced into Iranian apiaries, however, a multiplex PCR assay on archived samples from five provinces of Iran collected in 2004-2013 revealed V. ceranae-positive samples(Modirrousta et al. 2014). Regarding V. ceranae spore nature, such as resistance to high temperatures (as high as 60 °C) and desiccation and more sensitivity to very cold temperatures(Fenoy et al. 2009), it has been asserted that V. ceranae can be more prevalent in hot and dry regions(Fries 2010;Gisder et al. 2010;Higes et al. 2010a), such as the Middle-Mast climates and Iran.With some exceptions(Paxton et al. 2007;Giersch et al. 2009;Gisder et al. 2010;Fries 2010;Bollan et al. 2013;Forsgren and Fries 2013;González et al. 2019;Ostroverkhova et al. 2020), either the prevalence of V. ...
... Although it still remains unknown when and how this microsporidian pathogen has introduced into Iranian apiaries, however, a multiplex PCR assay on archived samples from five provinces of Iran collected in 2004-2013 revealed V. ceranae-positive samples(Modirrousta et al. 2014). Regarding V. ceranae spore nature, such as resistance to high temperatures (as high as 60 °C) and desiccation and more sensitivity to very cold temperatures(Fenoy et al. 2009), it has been asserted that V. ceranae can be more prevalent in hot and dry regions(Fries 2010;Gisder et al. 2010;Higes et al. 2010a), such as the Middle-Mast climates and Iran.With some exceptions(Paxton et al. 2007;Giersch et al. 2009;Gisder et al. 2010;Fries 2010;Bollan et al. 2013;Forsgren and Fries 2013;González et al. 2019;Ostroverkhova et al. 2020), either the prevalence of V. ...
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Nosemosis caused by Vairimorpha ceranae is one of the most important threats to honeybee colonies worldwide. This study aimed to determine the prevalence and intensity of Vairimorpha infection in different types of colonies and locations in Iran. In October 2017 and May 2018, 376 colonies from 97 apiaries were selected for each month according to a randomly clustered design. By considering 3–5 colonies for each apiary, 20 adult bees as pooled samples were collected from each colony. In microscopic analysis, 46.52% and 46.1% of samples in May and October showed Vairimorpha spores, respectively. The infection intensities in May and October were 5.94 ± 0.19 (× 106) and 5.86 ± 0.23 (× 106) spores/bee in a pooled sample, respectively. The mean infection intensity ranged from 1.8 to 12.5 (× 106) spores/bee. Statistically, there were no significant differences in the prevalence and intensity of V. ceranae infection between May and October samples. No significant differences were found among the prevalence rates of infection in the types of colonies; however, the intensity was significantly higher in migratory and mountainous colonies in May and only in migratory colonies in October. There was a significant correlation between the prevalence and intensity of V. ceranae infection (r2 = 0.695). PCR analysis showed that the samples were only infected with V. ceranae. No intraspecific variation to V. ceranae was found by direct sequencing of the amplified fragment of 16S rRNA. The obtained sequence was mainly 100% similar to those of V. ceranae isolates from European countries.
... It can infect the gastrointestinal tract of honey bees that ingest N. ceranae spores in contaminated food. Furthermore, infected bees can pass spores to uninfected ones via trophallaxis (feeding one another), with this serving as a primary route of disease transmission (Fries, 2010;Smith, 2012). There is also evidence that honey bees can transmit N. ceranae sexually between the adult reproductive bees (Roberts et al., 2015). ...
... Mature spores are released from their host cells into the gut lumen via cell lysis. There, they infect neighboring cells or are eliminated from the bees via defecation (Fries, 2010). Finally, N. ceranae infected bees died within a few weeks (Fries, 2010;Suwannapong et al., 2010). ...
... There, they infect neighboring cells or are eliminated from the bees via defecation (Fries, 2010). Finally, N. ceranae infected bees died within a few weeks (Fries, 2010;Suwannapong et al., 2010). ...
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The health of western honey bees (Apis mellifera L.) is constantly affected by Nosema ceranae, a microsporidian threat to colonies worldwide. We extracted propolis, a natural product exhibiting antimicrobial properties, from honey bee hives, fed it to worker bees before or after infection with N. ceranae, and determined its ability to protect bees from and treat them after infection. Protection from N. ceranae was tested using newly emerged bees that were group fed (50 bees/group) 50% propolis extract for 2, 4 and 8 d prior to infection with 1 􀀂 105 spores per bee. Treatment of N. ceranae was tested on newly emerged bees that were individually force-fed with 2 mL of 50% (w/v) sucrose solution containing 1 􀀂 105 spores per bee and then treated with 50% propolis in 50% sucrose solution (v/v) at 0, 2, 4 and 8 d post infection (p.i.). Positive (sugar water þ N. ceranae), negative (sugar water only), and solvent (ethanol þ sugar water) controls were included in both studies. Propolis fed to honey bees for 4 or 8 d before infection was associated with significantly reduced mortality, infectivity, and N. ceranae infection rates compared to the positive controls. Moreover, providing propolis to infected honey bees at d 0, 2, and 4 p.i. significantly reduced bee mortality, infection, and infectiv-ity rates compared to the positive controls and bees treated 8 d p.i. Therefore, propolis extracted from honey bee hives may be a promising alternative approach to antibiotics for protecting colonies from Nosema disease.
... Within the hive, Nosema can be transferred by ingesting faeces from infected bees, and from ingesting stored pollen and honey. Survivability of Nosema in stored resources is temperature and species dependent, with N. apis tolerating lower temperatures than N. ceranae (Fries, 2010). It is worth noting that Nosema is not transmitted by contact between bees; only by ingestion (Goblirsch, 2014;Goblirsch 2018;Traver, 2011;Graystock et al 2015). ...
... Lower survival temperature for Nosema ceranae (Gisder et al, 2010 Lower survival temperature for Nosema Apis (Fries, 2010). ...
... The nosemosis type C is a disease of honey bees caused by the microsporidium Nosema ceranae [1,2]. The parasite, native of the Asian honey bee Apis cerana [3], spread rapidly around the world becoming one of the diseases causing colony decline and collapse in the European honey bee Apis mellifera, often replacing Nosema apis [4][5][6][7][8]. ...
... The two coding sequences are separated from each other by a non-coding one called Internal Transcribed Spacer (ITS), while between each repeated unit of rDNA there is another non-coding sequence called Intergenic Spacer (IGS) [29]. These DNA sequences are frequently used for phylogenetic studies of eukaryotic organisms [1], and the same approach was used to study N. ceranae also [3]. Therefore, rDNA has also been used to distinguish the different species belonging to the genus Nosema, especially N. ceranae from N. apis, both capable of infecting A. mellifera [30][31][32][33], as well as to evaluate the degree of intraspecific variability of those two microsporidia [31,34,35].In general, the quantification of N. ceranae abundance relies on primer pairs designed on different sequences of the same SSU-rRNA (16S rRNA) [36]. ...
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The microsporidian Nosema ceranae is a severe threat to the western honey bee Apis mellifera, as it is responsible for nosemosis type C, which leads the colonies to dwindle and collapse. Infection quantification is essential to clinical and research aims. Assessment is made often with molecular assays based on rRNA genes, which are present in the N. ceranae genome as multiple and polymorphic copies. This study aims to compare two different methods of Real-Time PCR (qPCR), respectively relying on the 16S rRNA and Hsp70 genes, the first of which is described as a multiple and polymorphic gene. Young worker bees, hatched in the laboratory and artificially inoculated with N. ceranae spores, were incubated at 33 °C and subject to different treatment regimens. Samples were taken post-infection and analyzed with both qPCR methods. Compared to Hsp70, the 16S rRNA method systematically detected higher abundance. Straightforward conversion between the two methods is made impossible by erratic 16s rRNA/Hsp70 ratios. The 16s rRNA polymorphism showed an increase around the inoculated dose, where a higher prevalence of ungerminated spores was expected due to the treatment effects. The possible genetic background of that irregular distribution is discussed in detail. The polymorphic nature of 16S rRNA showed to be a limit in the infection quantification. More reliably, the N. ceranae abundance can be assessed in honey bee samples with methods based on the single-copy gene Hsp70.
... Therefore, there are considerable amounts of (undigested) sugar in the feces (which is attractive to other bees), and bees lick and eat it (the oral-fecal route of infection). Combs contaminated with feces are the basic source of infection [16]. Nosema spores also spread through honey, pollen, bee bread, syrup, and other routes, thus trophallaxis (oral-oral food exchange between insects) is a direct way of sharing the spores between bees ( Figure 1) [17,18]. ...
... Both Nosema species exhibit different temperature tolerances. N. ceranae is very sensitive to freezing, while N. apis can be stored in a freezer without losing much vitality [16]. However, in contrast to N. apis, N. ceranae can survive above 60 • C [26]. ...
Article
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Nosema apis and Nosema ceranae are dangerous parasites of the honey bee (Apis mellifera). N. ceranae is more pathogenic and, nowadays, more widespread than N. apis. There are also cases of mixed infections or infections of only N. apis. Both N. apis and N. ceranae can lead to the weakening or death of A. mellifera colonies. It is crucial to make a fast and reliable diagnosis to monitor the disease and to start the correct treatment. Additionally, there is a need for further research on the pathogenicity of Nosema spp. and also on their prevalence in different regions of the world. In this paper, we present reliable diagnostic methods for Nosema spp. infection in honey bees and list the advantages and disadvantages of each method. We have also included basic information about nosemosis and the majority of diagnostic methods in order to provide a source of knowledge for veterinarians and researchers.
... V. ceranae infections mainly occurred in midgut epithelium cells and have characteristics of typical chronic infections [10], including hormonal and immune responses [11,12] and subtle alterations of behavior [13]. Many studies suggest that V. ceranae significantly reduces longevity, but this effect is not universally reported [14,15]; differences among repeat trials made mortality insignificant in cages [16] and hives [17], which suggested unknown factors affect the mortality caused by the infection. In addition, feeding pollen, the major protein and polysaccharide source in the honey bee diet, increased the host longevity and the V. ceranae numbers [18,19]. ...
... [28], Snodgrassella alvi [27,30], and Gilliamella apicola [26], led to the hypothesis that these enhanced bacteria may positively affect host homeostasis that possibly led to the tolerance and the mortality discrepancies in studies. Foragers can carry millions of spores without obvious symptoms, and the mortality discrepancies among studies using different subspecies of honey bees, foods, and environmental settings [14] although no specific trend was noted in studies. Many associated core bacteria are considered probiotics in other animals and are expected to add health benefits, including protection from pathogens [41,42] and additional lifespan [43]. ...
Article
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Vairimorpha (Nosema) ceranae is the most common eukaryotic gut pathogen in honey bees. Infection is typically chronic but may result in mortality. Gut microbiota is a factor that was recently noted for gut infectious disease development. Interestingly, studies identified positive, instead of negative, associations between core bacteria of honey bee microbiota and V. ceranae infection. To investigate the effects of the positive associations, we added isomaltooligosaccharide (IMO), a prebiotic sugar also found in honey, to enhance the positive associations, and we then investigated the infection and the gut microbiota alterations using qPCR and 16S rRNA gene sequencing. We found that infected bees fed IMO had significantly higher V. ceranae spore counts but lower mortalities. In microbiota comparisons, V. ceranae infections alone significantly enhanced the overall microbiota population in the honey bee hindgut and feces; all monitored core bacteria significantly increased in the quantities but not all in the population ratios. The microbiota alterations caused by the infection were enhanced with IMO, and these alterations were similar to the differences found in bees that naturally have longer lifespans. Although our results did not clarify the causations of the positive associations between the infections and microbiota, the associations seemed to sustain the host survival and benefit the pathogen. Enhancing indigenous gut microbe to control nosema disease may result in an increment of bee populations but not the control of the pathogen. This interaction between the pathogen and microbiota potentially enhances disease transmission and avoids the social immune responses that diseased bees die prematurely to curb the disease from spreading within colonies.
... A diferencia de los Estados Unidos de América donde las infecciones causadas por N. apis o N. ceranae pueden ser controladas con la aplicación de fumagilina, en diversos países de Europa (26) así como en México, este antibiótico no está autorizado para el control de la nosemosis debido a la toxicidad que puede representar para los humanos, por lo que cualquier residuo que quede en la miel de las colonias que se encuentren bajo tratamiento, representa un riesgo directo para el consumidor (27) . ...
Article
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Resumen: Nosema ceranae, es un parásito obligatorio del intestino medio de las abejas melíferas que causa destrucción de las células epiteliales afectando la digestión y asimilación del alimento, impactando negativamente el desarrollo y sobrevivencia de las colonias de abejas. Con la finalidad de reducir los efectos negativos, se evaluó la eficacia del timol en el control de esta parasitosis. El estudio se realizó en dos apiarios experimentales con un total de 56 colonias de abejas distribuidas en tres grupos experimentales: G1) 18 colonias que recibieron tratamiento con fumagilina como producto de referencia (25.2 mg de fumagilina/semana); G2) 19 colonias que recibieron tratamiento con timol como producto alternativo (66 mg de cristales/semana) y G3) 19 colonias que no recibieron ningún tratamiento (grupo testigo). Los tratamientos con la fumagilina y timol se aplicaron a través del jarabe de azúcar una vez por semana durante cuatro semanas consecutivas. Los niveles de infección de N. ceranae se estimaron en el macerado del abdomen de 60 abejas adultas colectadas de cada colonia
... A diferencia de los Estados Unidos de América donde las infecciones causadas por N. apis o N. ceranae pueden ser controladas con la aplicación de fumagilina, en diversos países de Europa (26) así como en México, este antibiótico no está autorizado para el control de la nosemosis debido a la toxicidad que puede representar para los humanos, por lo que cualquier residuo que quede en la miel de las colonias que se encuentren bajo tratamiento, representa un riesgo directo para el consumidor (27) . ...
Article
Full-text available
Nosema ceranae, es un parásito obligatorio del intestino medio de las abejas melíferas que causa destrucción de las células epiteliales afectando la digestión y asimilación del alimento, impactando negativamente el desarrollo y sobrevivencia de las colonias de abejas. Con la finalidad de reducir los efectos negativos, se evaluó la eficacia del timol en el control de esta parasitosis. El estudio se realizó en dos apiarios experimentales con un total de 56 colonias de abejas distribuidas en tres grupos experimentales: G1) 18 colonias que recibieron tratamiento con fumagilina como producto de referencia (25.2 mg de fumagilina/semana); G2) 19 colonias que recibieron tratamiento con timol como producto alternativo (66 mg de cristales/semana) y G3) 19 colonias que no recibieron ningún tratamiento (grupo testigo). Los tratamientos con la fumagilina y timol se aplicaron a través del jarabe de azúcar una vez por semana durante cuatro semanas consecutivas. Los niveles de infección de N. ceranae se estimaron en el macerado del abdomen de 60 abejas adultas colectadas de cada colonia experimental. Los resultados al final de los tratamientos indican que las colonias que recibieron fumagilina (G1) disminuyeron sus niveles de infección de 123,529 a 1,805 esporas por abeja; para G2 (timol), la reducción fue de 133,438 a 28,099 esporas por abeja, y para las colonias del grupo testigo (G3) fue de 119,306 a 36,447 esporas por abeja. Los tres grupos experimentales presentaron diferencias estadísticas significativas en los niveles de infección de N. ceranae al final de los tratamientos. La fumagilina presentó una mayor eficacia (95.2 %) en comparación con el timol la, cual fue baja (31.1 % de eficacia) indicando que se requieren estudios adicionales para determinar la concentración más efectiva a nivel de colonia bajo condiciones tropicales de Yucatán, a fin de que este aceite esencial de origen vegetal sea incorporado como producto alternativo para el control de esta parasitosis. Palabras clave: Nosema ceranae, Nosemosis, Fumagilina, Timol, Eficacia, Apis mellifera.
... Honey bees are key pollinators of both wild plant communities and agricultural crops, they are important to the environment as well as the food supply (Calderone, 2012). Nosema ceranae and Nosema apis are major causes of microsporidiosis in honey bees (Higes et al., 2008;Fries, 2010). N. ceranae is now the predominant microsporidium species seen in the western honey bee (Apis mellifera), which is the most important bee species for honey production and animal-mediated pollination (Williams et al., 2014). ...
Article
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Microsporidia are obligate intracellular, spore-forming parasitic fungi which are grouped with the Cryptomycota. They are both opportunistic pathogens in humans and emerging veterinary pathogens. In humans, they cause chronic diarrhea in immune-compromised patients and infection is associated with increased mortality. Besides their role in pébrine in sericulture, which was described in 1865, the prevalence and severity of microsporidiosis in beekeeping and aquaculture has increased markedly in recent decades. Therapy for these pathogens in medicine, veterinary, and agriculture has become a recent focus of attention. Currently, there are only a few commercially available antimicrosporidial drugs. New therapeutic agents are needed for these infections and this is an active area of investigation. In this article we provide a comprehensive summary of the current as well as several promising new agents for the treatment of microsporidiosis including: albendazole, fumagillin, nikkomycin, orlistat, synthetic polyamines, and quinolones. Therapeutic targets which could be utilized for the design of new drugs are also discussed including: tubulin, type 2 methionine aminopeptidase, polyamines, chitin synthases, topoisomerase IV, triosephosphate isomerase, and lipase. We also summarize reports on the utility of complementary and alternative medicine strategies including herbal extracts, propolis, and probiotics. This review should help facilitate drug development for combating microsporidiosis.
... Fumagillin is approved in the United States and is widely used to control N. apis and N. ceranae infections. However, in many European countries (26) , as well as in Mexico, it is prohibited for nosemosis control due to its toxicity in humans; any residue remaining in honey from colonies under treatment represents a direct risk to the consumer (27) . Alternative nosemosis control products have been proposed. ...
Article
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Nosema ceranae is an obligatory parasite of the honeybee midgut. It destroys the epithelial cells, negatively affecting food digestion and assimilation, and impacting bee development and colony survival. Antifungals such as fumagillin effectively control N. ceranae but can be toxic to humans who consume honey from treated hives, and are prohibited in many countries, including Mexico. Essential oils from plants are promising alternative antifungals. An evaluation was done of the efficacy of the essential oil thymol in controlling N. ceranae in Africanized Apis mellifera colonies over a four-week period. A total of 56 colonies were distributed in three experimental groups: G1) 18 colonies treated with fumagillin (25.2 mg fumagillin/week); G2) 19 colonies treated with thymol (66 mg thymol crystals/week); and G3) 19 untreated colonies (control). Infection levels (N. ceranae spores/bee) were estimated in 60 adult bees from each colony. Fumagillin (G1) reduced infection levels from 123,529 to 1,805 spores/bee (95.2 % efficacy). Thymol (G2) reduced infection levels from 133,438 to 28,099 spores/bee (31.1 % efficacy). Infection levels also declined in the control group (G3), from 119,306 to 36,447 spores/bee. The clearly higher efficacy with fumagillin compared to thymol highlights the need for further trials to test different thymol concentrations, and administration frequencies and times. Under the present study conditions thymol was not effective against N. ceranae, but the pressing need for non-toxic antifungals for use in Africanized A. mellifera colonies in the tropics makes research on thymol and other essential oils imperative. Key words: Nosema ceranae, Nosemosis, Fumagillin, Thymol, Efficacy, Apis mellifera.
... These are the first data on experimental infection of the greater wax moth with the microsporidia N. apis and N. ceranae; besides, the infectivity of Nosema species to A. mellifera was previously mentioned [14,29,31]. Our results show that these Nosema species develop well in both G. mellonella and A. mellifera and that their infectivity starts within 6 days by completing their intracellular life cycle ( Figure 2). ...
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The study aims to prove the possibility of colonization of N. apis and N. ceranae to the intestine of the greater wax moth, detect the differences of greater wax moth based on the presence of Nosema species and examine the effect of Nosema species on the phenoloxidase level of greater wax moth compared with honeybees. Each group was fed on the 1st day of the experiment with its appropriate diet containing 106 Nosema spores per insect. Each group was checked daily, and dead insects were counted. Furthermore, changes in the level of expression of the phenoloxidase-related gene after Nosema spp. treatment on the 6th, 9th and 12th days, which was detected by Q-PCR, and the mRNA level of phenoloxidase gene were measured in all experiment groups with the CFX Connect Real-Time PCR Detection System. This study shows that Apis mellifera L. has a 66.7% mortality rate in mixed Nosema infections, a 50% mortality rate in N. ceranae infection, a 40% mortality rate in N. apis infection, while there is no death in G. mellonella. A significant difference was found in the mixed Nosema infection group compared to the single Nosema infection groups by means of A. mellifera and G. mellonella (Duncan, p < 0.05). G. mellonella histopathology also shows that Nosema spores multiply in the epithelial cells of greater wax moth without causing any death. The increase in the mRNA level of Phenoloxidase gene in A. mellifera was detected (Kruskal–Wallis, p < 0.05), while the mRNA level of the Phenoloxidase gene did not change in G. mellonella (Kruskal–Wallis, p > 0.05). These findings prove that the Nosema species can colonize into the greater wax moth, which contributes to the dissemination of these Nosema species between beehives.
... Midgut infection by this unicellular eukaryote causes energetic stress, epithelial damage, and when untreated, death [7][8][9][10][11][12]. Furthermore, infection is associated with a number of physiological and behavioral changes that likely affect individual contribution to the colony [10,11,[13][14][15]. ...
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The microsporidia Nosema ceranae is an obligate intracellular parasite that causes honey bee mortality and contributes to colony collapse. Fumagillin is presently the only pharmacological control for N. ceranae infections in honey bees. Resistance is already emerging, and alternative controls are critically needed. Nosema spp. exhibit increased sensitivity to heat shock, a common proteotoxic stress. Thus, we hypothesized that targeting the Nosema proteasome, the major protease removing misfolded proteins, might be effective against N. ceranae infections in honey bees. Nosema genome analysis and molecular modeling revealed an unexpectedly compact proteasome apparently lacking multiple canonical subunits, but with highly conserved proteolytic active sites expected to be receptive to FDA-approved proteasome inhibitors. Indeed, N. ceranae were strikingly sensitive to pharmacological disruption of proteasome function at doses that were well tolerated by honey bees. Thus, proteasome inhibition is a novel candidate treatment strategy for microsporidia infection in honey bees.
... In our study, N. ceranae was found almost exclusively in the North Island, with only two detections in the South Island being observed over the study period. There has been some conjecture in the literature that N. ceranae may displace N. apis (Klee et al., 2007;Fries, 2010;Yoshiyama & Kimura, 2011) but this hypothesis does not appear to be supported in our study. Instead, we observed similar results to a 12-year longitudinal study in Germany where both nosema species were found to co-exist within 230 managed colonies (Gisder et al., 2017). ...
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In New Zealand, the introduced honey bee (Apis mellifera) is a valuable production animal, providing pollination services for horticultural crops and significant export volumes of honey, especially mānuka honey. Honey bees in New Zealand are free from a number of significant diseases and pests such as European foulbrood, acarine disease, small hive beetle, Israeli acute paralysis virus and tropilaelaps mites. We sought to determine the health status of honey bees in New Zealand using a longitudinal study that followed 60 beekeepers over 2.5 years, ascertaining disease and pest status in their elected study apiary and interviewing them every spring and autumn. Participant beekeepers accounted for the management of approximately 12% of the beehives registered in New Zealand. Differences in beekeeping practices were observed between the North Island and the South Island. Nosema ceranae was found almost exclusively on the North Island and did not displace Nosema apis over the course of the study. Lotmaria passim showed a reverse-phase seasonality to nosema, peaking in autumn at near 100% prevalence. The prevalence of Varroa in apiaries varied seasonally between 45.0% and 46.7% in spring and between 65.0% and 69.5% in autumn, with most infestation rates below 3 mites per 100 bees. The detection rate of symptomatic American foulbrood disease during our hive inspections was very low, between 0.00% and 0.85% hive-level prevalence dependent on the season. This study sets a foundation for understanding honey bee health in New Zealand.
... Nosema spp. can affect the productivity and survival of honey bees altering their longevity and behaviour, brood rearing and pollen collection [9,10]. It was also reported that co-infection by virus and N. ceranae in honey bees might be associated with colony collapse disorder (CCD) [11]. ...
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A progressive honey bee population decline has been reported worldwide during the last decades, and it could be attributed to several causes, in particular to the presence of pathogens and parasites that can act individually or in synergy. The health status of nine apiaries located in different areas of the Veneto region (northeast of Italy) was assessed for two consecutive years (2020 and 2021) in spring, during the resumption of honey bee activity, for determining the presence of known (Nosema spp., Varroa mite and viruses) and less known or emerging pathogens (Lotmaria passim and Crithidia mellificae) in honey bees. After honey bees sampling from each of the nine apiaries, Nosema apis, Nosema ceranae, L. passim, C. mellificae, ABPV, CBPV, IAPV, KBV, BQCV, SBV, DWV-A, DWV-B and V. destructor were investigated either by microscopic observation or PCR protocols. The viruses BQCV, SBV, CBPV followed by N. ceranae and L. passim were the most prevalent pathogens, and many of the investigated hives, despite asymptomatic, had different degrees of co-infection. This study aimed to highlight, during the resumption of honey bee activity in spring, the prevalence and spreading in the regional territory of different honey bee pathogens, which could alone or synergistically alter the homeostasis of bees colonies. The information gathered would increase our knowledge about the presence of these microorganisms and parasites in the territory and could contribute to improve beekeepers practice.
... The microsporidium Nosema ceranae is an obligate intracellular parasite that colonizes the epithelial cells of the honey bee gut. It is frequently associated in certain regions with colony losses (Fries, 2010;Fries et al., 2006). ...
Thesis
Les données scientifiques actuelles suggèrent un déclin de la diversité et de l’abondance des insectes, y compris les abeilles domestiques Apis mellifera. Ces dernières sont confrontées à de fortes pertes de colonies dans plusieurs régions du monde telles que l’ouest de l’Europe et les États-Unis. De nombreuses études suggèrent que l’origine du déclin des colonies d’abeilles est multicausale et identifient les pesticides et les agents pathogènes comme étant les principaux contributeurs à ce déclin. La co-exposition des abeilles à de multiples pesticides et l’infection par plusieurs pathogènes constituent un phénomène courant. Cependant, les recherches sur les effets des mélanges de pesticides n’ont pas fait l’objet d’un intense développement. Ainsi, les travaux conduits dans le cadre de cette thèse ont été focalisés sur la détermination de la toxicité des mélanges de pesticides, appliqués à des niveaux d’exposition environnementaux, en présence d’un agent pathogène. Le choix s’est porté sur l’étude des interactions entre un insecticide néonicotinoïde, l’imidaclopride, un fongicide azole, le difénoconazole, et un herbicide, le glyphosate, en présence de l’agent pathogène Nosema ceranae. Les résultats des différentes études effectuées durant cette thèse, révèlent la complexité des études sur les mélanges de pesticides. Ces travaux nous ont permis de constater que les effets d’un mélange de pesticides peuvent fortement varier en fonction des concentrations des pesticides constituant le mélange. L’augmentation du nombre de substances et du niveau d’exposition, n’induit pas nécessairement une augmentation de la toxicité du mélange. De plus, les effets du mélange peuvent varier en fonction de la séquence d’exposition aux pesticides et de l’état sanitaire des abeilles. Les mélanges de pesticides affectent l’état physiologique des abeilles suite à une réponse systémique liée à des perturbations de mécanisme généraux tels que le stress oxydant. Cependant, ces trois pesticides, seuls et en mélanges n’ont aucun effet sur l’installation du microbiote intestinal à des niveaux d’exposition environnementaux.
... Currently, N. ceranae could be detected in colonies all over the world. N. ceranae infestation results in a battery of negative impacts on the honey bee host such as shortened life span, energy stress, immunosuppression, cell apoptosis inhibition [3][4][5][6], earlier foraging activity, and impaired navigation and cognitive ability [7,8]. A close connection between N. ceranae and colony collapse disorder (CCD) has been suggested by several studies [9,10]. ...
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Apis cerana is the original host for Nosema ceranae, a widespread fungal parasite resulting in honey bee nosemosis, which leads to severe losses to the apiculture industry throughout the world. However, knowledge of N. ceranae infecting eastern honey bees is extremely limited. Currently, the mechanism underlying N. ceranae infection is still largely unknown. Based on our previously gained high-quality transcriptome datasets derived from N. ceranae spores (NcCK group), N. ceranae infecting Apis cerana cerana workers at seven days post inoculation (dpi) and 10 dpi (NcT1 and NcT2 groups), comparative transcriptomic investigation was conducted in this work, with a focus on virulence factor-associated differentially expressed genes (DEGs). Microscopic observation showed that the midguts of A. c. cerana workers were effectively infected after inoculation with clean spores of N. ceranae. In total, 1411, 604, and 38 DEGs were identified from NcCK vs. NcT1, NcCK vs. NcT2, and NcT1 vs. NcT2 comparison groups. Venn analysis showed that 10 upregulated genes and nine downregulated ones were shared by the aforementioned comparison groups. The GO category indicated that these DEGs were involved in a series of functional terms relevant to biological process, cellular component, and molecular function such as metabolic process, cell part, and catalytic activity. Additionally, KEGG pathway analysis suggested that the DEGs were engaged in an array of pathways of great importance such as metabolic pathway, glycolysis, and the biosynthesis of secondary metabolites. Furthermore, expression clustering analysis demonstrated that the majority of genes encoding virulence factors such as ricin B lectins and polar tube proteins displayed apparent upregulation, whereas a few virulence factor-associated genes such as hexokinase gene and 6-phosphofructokinase gene presented downregulation during the fungal infection. Finally, the expression trend of 14 DEGs was confirmed by RT-qPCR, validating the reliability of our transcriptome datasets. These results together demonstrated that an overall alteration of the transcriptome of N. ceranae occurred during the infection of A. c. cerana workers, and most of the virulence factor-related genes were induced to activation to promote the fungal invasion. Our findings not only lay a foundation for clarifying the molecular mechanism underlying N. ceranae infection of eastern honey bee workers and microsporidian–host interaction.
... Larvae emerge from between the head and thorax of their dead host to pupariate, up to 13 larvae can emerge from a single host in field conditions. Core et al. (2012) demonstrated that some phorid larvae and adults harbour Nosema ceranae and the deformed wing virus (DWV), suggesting that zombie flies may transmit bee pathogens linked to colony mortality (de Miranda and Genersch 2010;Fries 2010;Steinhauer et al. 2018). In bumble bees, A. borealis infestation shortens adult lifespan by up to 70% (Otterstatter et al. 2002), but it is currently difficult to draw firm conclusions about the effects of phorid parasitism on bumblebee and honey bee populations (Cohen et al. 2017). ...
Article
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Apocephalus borealis is a parasitoid of hymenopterans native to North America that also attacks introduced honey bees (Apis mellifera). Parasitism by this species has been associated with infested bees absconding the hive and dying outside. The flies can also harbour viral infections and nosematosis. Recently, nucleotide sequences identical to A. borealis were reported from bulk screenings of honey bees from Belgium and South Korea, although no adult flies have been collected. To predict the potential invasion risk of A. borealis across the world, we constructed a MaxEnt species distribution model based on occurrence data from North America submitted to the citizen science project ZomBee Watch (zombeewatch.org) and from museum specimens. The results have shown that extensive parts of Europe, the Mediterranean Basin, Asia Minor, southern Africa, eastern Asia, Australasia, and North and South America have high degrees of climatic suitability for invasion, suggesting that the fly could establish in these regions. The potential invasion range is expected to stay similar under different climate change scenarios. We discuss the status of A. borealis as an invasive species and measures that can be taken to reduce the risk of its introduction outside of North America. Our results highlight A. borealis as a potential threat to honey bee health worldwide that requires urgent attention of international veterinary bodies to prevent its spread.
... N. ceranae was first described in the Asian honeybee (Apis cerana), and it replaced N. apis, although not generally, in European honeybees (A. mellifera) around 3 decades ago [23][24][25][26][27][28][29][30]. According to a study by Gisder et al. (2017), N. apis and N. ceranae show different multiplication rates in cell culture, but this is possibly not relevant in vivo [24]. ...
Article
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Honeybee populations have locally and temporally declined in the last few years because of both biotic and abiotic factors. Among the latter, one of the most important reasons is infection by the microsporidia Nosema ceranae, which is the etiological agent of type C nosemosis. This species was first described in Asian honeybees (Apis cerana). Nowadays, domestic honeybees (Apis mellifera) worldwide are also becoming infected due to globalization. Type C nosemosis can be asymptomatic or can cause important damage to bees, such as changes in temporal polyethism, energy and oxidative stress, immunity loss, and decreased average life expectancy. It causes drastic reductions in workers, numbers of broods, and honey production, finally leading to colony loss. Common treatment is based on fumagillin, an antibiotic with side effects and relatively poor efficiency, which is banned in the European Union. Natural products, probiotics, food supplements, nutraceuticals, and other veterinary drugs are currently under study and might represent alternative treatments. Prophylaxis and management of affected colonies are essential to control the disease. While N. ceranae is one potential cause of bee losses in a colony, other factors must also be considered, especially synergies between microsporidia and the use of insecticides.
... After the multiplication of the pathogen, spores are released from the damaged cells, continuing the invasion of not only the surrounding tissues but also other bees on leaving the host. The midgut of the bees is most severely affected (Fries, 2010), but research has shown that some other tissues and/or organs, such as the salivary and hypopharyngeal glands, ovaries (Steche, 1960;Sokolov and Grobov, 1963), the brain tissue (Gisder et al., 2010), and even the haemolymph (Glavinic et al., 2014) are not spared. Some research revealed that bees with nosemosis show increased hunger in comparison with their healthy counterparts, which implies energetic stress (Stanimirovic et al., 2019). ...
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Nosema ceranae, a microsporidium species, is among the most common causes of bee diseases. The positive effect of Agaricus bisporus mushroom extract on the survival and immunity of Nosema-infected bees has been reported recently. The effect could be achieved by stimulating the expression of immune-related genes, but also by suppressing nosemosis. The aim of this work was to determine the effect of A. bisporus extract on the oxidative status of bees infected with N. ceranae. In a cage experiment on newly hatched bees, the effect of aqueous extract of champignon (A. bisporus, strain A15) was investigated. Six groups were formed: three groups were infected and received A. bisporus extract through food at different times (days 1, 3, and 6 after hatching), one group received the extract but was not infected (treatment control), one was only infected with Nosema (positive control) and one was neither infected nor received the extract (negative control). The effects were examined on samples taken on days 7 and 15 of the study. The activities of the antioxidant enzymes catalase (CAT), superoxide dismutase (SOD) and glutathione S-transferase (GST) and the concentrations of malondialdehyde (MDA) were determined. In comparison to the positive control, the enzyme activities and MDA concentrations were significantly lower in the groups fed with the mushroom extract supplement. In the negative control, the level of oxidative stress was lower than in the positive control. In comparison with the other groups, the values mostly did not differ significantly. The oxidative status of bees infected with N. ceranae was significantly better if they were fed with the A. bisporus extract.
... N. ceranae and V. destructor (the main vector of DWV) originate from Asian countries and can replicate in a warm environment [17,82]. The apiary in the east Emilia-Romagna has a closer proximity to the sea, which contributes to a more suitable environment for N. ceranae and DWV infections [83][84][85][86][87]. Additionally, in 2021, a higher average temperature was recorded in Romagna (17 • C) than in Emilia (14 • C), creating a more suitable environment for these organisms (https://simc.arpae.it/dext3r/ ...
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The recent decades witnessed the collapse of honey bee colonies at a global level. The major drivers of this collapse include both individual and synergic pathogen actions, threatening the colonies’ survival. The need to define the epidemiological pattern of the pathogens that are involved has led to the establishment of monitoring programs in many countries, Italy included. In this framework, the health status of managed honey bees in the Emilia–Romagna region (northern Italy) was assessed, throughout the year 2021, on workers from 31 apiaries to investigate the presence of major known and emerging honey bee pathogens. The prevalence and abundance of DWV, KBV, ABPV, CBPV, Nosema ceranae, and trypanosomatids (Lotmaria passim, Crithidia mellificae, Crithidia bombi) were assessed by molecular methods. The most prevalent pathogen was DWV, followed by CBPV and N. ceranae. Trypanosomatids were not found in any of the samples. Pathogens had different peaks in abundance over the months, showing seasonal trends that were related to the dynamics of both bee colonies and Varroa destructor infestation. For some of the pathogens, a weak but significant correlation was observed between abundance and geographical longitude. The information obtained in this study increases our understanding of the epidemiological situation of bee colonies in Emilia–Romagna and helps us to implement better disease prevention and improved territorial management of honey bee health.
... The apparently recent spread of N. ceranae has been proposed to be due to a jump to A. mellifera from A. cerana, which is native to southern and southeastern Asia where it likely long co-existed with N. ceranae (Fries et al. 1996;Fries 2010). In East Asia, A. cerana has been domesticated for several thousand years (Dinh and Pham 2001;Xu et al. 2009), whereas A. mellifera was probably first introduced there from Hong Kong in 1947 but was mostly introduced during the 1960-1980s when A. mellifera was imported in relatively large numbers from Russia and Cuba (Dinh and Pham 2001;P. ...
Article
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Nosema ceranae is believed to have been originally a parasite of the Asian honey bee, Apis cerana, in East Asia that later infected the Western honey bee, Apis mellifera, followed by a worldwide spread. To examine if that possibly affected the genetics of the parasite, A. mellifera samples infected with N. ceranae were collected from seven locations across the world to compare the genetic variation of the parasite within its putative invasive range (Iran, Ontario-Canada, Alberta-Canada, New York-United States of America, Mexico and Argentina) to its native range (Vietnam) using SNPs in the translation elongation factor-1 alpha sequence and three SSRs. Both type of markers detected the highest genetic variation in Vietnam. The SNPs revealed that the most common variant in Vietnam was the type found in all other locations with no variation detected in the invasive range. The SSRs, however, showed variation in populations in the invasive range with three groups: Iran with Alberta-Canada, Mexico with Argentina, and Ontario-Canada with New York-United States of America. These groupings may be related to the international movement of bees and beekeeping products. The genetic variation of N. ceranae supports the hypothesis that the most likely origin of N. ceranae was East Asia, and that the parasite subsequently spread throughout the world.
... They cause destructive epizootics of domesticated insects. The microsporidium V. ceranae, firstly described in the Asian honeybee Apis cerana (Fries et al., 1996), is widely spread around the world (Fries, 2010) and associated with honeybee colony losses (Martín-Hernández et al., 2018), at least in southern European countries (Gisder and Genersch, 2015). Fumagillin, an antibiotic found in the fungus Aspergillus fumigatus, had been used to control honeybee microsporidiosis for many years (Katznelson and Jamieson, 1952;Bailey, 1953;Williams et al., 2008;van den Heever et al., 2014). ...
... Both N. apis and N. ceranae are the etiological agents of nosemosis, one of the adult honey bee's most widespread and serious diseases, causing significant economic losses to beekeepers [5,[17][18][19]. N. apis is responsible for nosemosis type A, a disease that increases bee mortality in winter and causes a slow build-up in spring, making bees weak and reducing honey yield [20]. Field experiments demonstrated that N. apis infection is also responsible for the onset of foraging at a younger age than in healthy worker bees [21,22]. ...
Article
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Nosemosis is a disease triggered by the single-celled spore-forming fungi Nosema apis and Nosema ceranae, which can cause extensive colony losses in honey bees (Apis mellifera L.). Fumagillin is an effective antibiotic treatment to control nosemosis, but due to its toxicity, it is currently banned in many countries. Accordingly, in the beekeeping sector, there is a strong demand for alternative ecological methods that can be used for the prevention and therapeutic control of nosemosis in honey bee colonies. Numerous studies have shown that plant extracts, RNA interference (RNAi) and beneficial microbes could provide viable non-antibiotic alternatives. In this article, recent scientific advances in the biocontrol of nosemosis are summarized.
... The fact that microsporidia secret the enzyme hexokinase into the host cytoplasm (Cuomo et al., 2012;Senderskiy et al., 2014;Ferguson and Lucocq, 2019) and the data that its RNAi suppresses the parasite intracellular growth (Huang et al., 2018b) suggests that this enzyme may be such target for scFv Abs. Previously, we overexpressed in E. coli hexokinase of the microsporidium V. ceranae (VcHK) which is a widely spread and highly pathogenic parasite of honey bee Apis mellifera (Fries, 2010) implicated in colony losses . The recombinant enzyme, purified by IMAC (Immobilized Metal Chelate Affinity Chromatography), demonstrated kinetic characteristics similar to those of HKs from other parasitic and free-living organisms . ...
Article
Secretion of hexokinase (HK) by microsporidia into infected cells suggests an important role this enzyme for the intracellular development of parasites. To verify whether the expression of HK-specific antibodies in the host cell cytoplasm can suppress the growth of microsporidia, we constructed an immune library of recombinant scFv fragments against the enzyme of the honey bee pathogen Vairimorpha (Nosema) ceranae (VcHK) with a representativeness of about 5 million bacterial transformants. Two variants of VcHK-specific recombinant antibodies were selected by library panning and expressed in lepidopteran Sf9 cell line. Infecting of cells expressing two selected and control scFv fragments with V. ceranae spores was followed by their cultivation for 4 days. Analysis of parasite β-tubulin as well as spore wall protein SWP32 transcripts in infected cultures by reverse transcription PCR and real-time qPCR showed (1) V. ceranae growth in cells heterologous to bee pathogens, (2) its inhibition by one of the selected VcHK-specific recombinant antibodies. The latter result once again emphasizes an important role of microsporidia hexokinases in their relationships with infected host cells and suggests further focusing on the mechanisms of such suppression, as well as on the search for new V. ceranae - inhibiting scFv fragments.
... Honey bees, one of the most important groups of pollinating insects, play an irreplaceable role in the pollination of crops and flowering plants (2). However, in recent years, many studies have shown that honey bee populations are declining globally due to climate change (3), widespread use of agricultural pesticides (4,5), intensive agricultural development (6,7), habitat conversion (8,9) and specific parasites (10,11) such as bacteria and viruses. The alarming decline in honey bee population has attracted global attention. ...
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Understanding the cause of honey bee (Apis mellifera) population decline has attracted immense attention worldwide in recent years. Exposure to neonicotinoid pesticides is considered one of the most probable factors due to the physiological and behavioral damage they cause to honey bees. However, the influence of thiacloprid, a relatively less toxic cyanogen-substituted form of neonicotinoid, on honey bee (Apis mellifera L.) development is not well studied. The toxicity of sublethal thiacloprid to larvae, pupae, and emerging honey bees was assessed under laboratory conditions. We found that thiacloprid reduced the survival rate of larvae and pupae, and delayed the development of bees which led to lower bodyweight and size. Furthermore, we identified differentially expressed genes involved in metabolism and immunity though RNA-sequencing of newly-emerged adult bees. GO enrichment analysis identified genes involved in metabolism, catalytic activity, and transporter activity. KEGG pathway analysis indicated that thiacloprid induced up-regulation of genes related to glutathione metabolism and Toll-like receptor signaling pathway. Overall, our results suggest that chronic sublethal thiacloprid can affect honey bee colonies by reducing survival and delaying bee development.
Article
Nosemosis is one of the most dangerous infectious diseases of honeybees in Azerbaijan and the World. Nosema ceranae is the dominant species detected in Azerbaijan, and this study aimed to detect the prevalence of the infection in the country. For this purpose, an average of 100 honeybee samples were collected from 64 hives, 24 from three regions in the north and 40 from five areas in the south. In the lab, the abdomens of 50 bees from each group were dissected and crushed in a container, adding 50 ml of distilled water. According to obtained data after microscopic examination, the N. ceranae spores were found to have a high-level prevalence in northern regions (45.8% average) than in the southern areas (22.5% average) of Azerbaijan. Molecular diagnoses of Nosema-positive samples have already been made with PCR and N. ceranae has been detected from all regions. Data show us that the Nosemosis is common in Azerbaijan and is a significant thread in the beekeeping industry.
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Bee health is a growing global concern due to the decline of colonies that has been observed in many countries. Studies about pathogen detection in Brazil are important to understand the health status of Africanized honeybees in the country, and we aimed to evaluate the presence of pathogens in Africanized honey bees in Bahia, Brazil. We tested by PCR and RT-PCR a total of 180 A. mellifera colonies from 60 municipalities screening for 13 of the most common honeybee pathogens (fungi, bacteria, and viruses). We detected eight pathogens among 73% of our sampled honeybee colonies across Bahia state: Nosema ceranae (fungus), Melissococcus plutonius, Paenibacillus larvae (bacteria), and viruses acute bee paralysis virus (ABPV), black queen cell virus (BQCV), deformed wing virus (DWV), Israeli acute paralysis virus (IAPV), and Chronic bee paralysis virus (CBPV). Nosema ceranae (fungus) was the pathogen most present in the samples (73%) followed by ABPV (55%) and both pathogens were also the most frequent among the samples. Multiple infections were in 58% of the samples and again N. ceranae and ABPV were the most prevalent pathogens. The Africanized honeybees from Bahia presented pathogens that can cause colony loss and further studies are necessary to evaluate the impact of those pathogens on Africanized honeybees and colony production.
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Flowers can be transmission platforms for parasites that impact bee health, yet bees share floral resources with other pollinator taxa, such as flies, that may be hosts or non-host vectors (i.e., mechanical vectors) of parasites. Here, we assessed whether the fecal-orally transmitted gut parasite of bees, Crithidia bombi , can infect Eristalis tenax flower flies. We also investigated the potential for two confirmed solitary bee hosts of C. bombi , Osmia lignaria and Megachile rotundata , as well as two flower fly species, Eristalis arbustorum and E. tenax, to transmit the parasite at flowers. We found that C. bombi did not replicate (i.e., cause an active infection) in E. tenax flies. However, 93% of inoculated flies defecated live C. bombi in their first fecal event, and all contaminated fecal events contained C. bombi at concentrations sufficient to infect bumble bees. Flies and bees defecated inside the corolla (flower) more frequently than other plant locations, and flies defecated at volumes comparable to or greater than bees. Our results demonstrate that Eristalis flower flies are not hosts of C. bombi , but they may be mechanical vectors of this parasite at flowers. Thus, flower flies may amplify or dilute C. bombi in bee communities, though current theoretical work suggests that unless present in large populations, the effects of mechanical vectors will be smaller than hosts.
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Honey bees (Apis mellifera) perform pollination service for many agricultural crops and contribute to the global economy in agriculture and bee products. However, honey bee health is an ongoing concern, as illustrated by persistent local population decline, caused by some severe bee diseases (e.g., nosemosis, AFB, EFB, chalkbrood). Three natural recipes are in development based on the bioactive compounds of different plants extract (Agastache foeniculum, Artemisia absinthium, Evernia prunastri, Humulus lupulus, Laurus nobilis, Origanum vulgare and Vaccinium myrtillus), characterised by HPLC-PDA. The antimicrobial activity of these recipes was tested in vitro against Paenibacillus larvae, Paenibacillus alvei, Brevibacillus laterosporus, Enterococcus faecalis, Ascosphaera apis and in vivo against Nosema ceranae. A mix of 20% blueberry, 40% absinthium, 10% oakmoss, 10% oregano, 10% Brewers Gold hops, 5% bay laurel and 5% anise hyssop extract showed the strongest antibacterial and antifungal activity. Combing several highly active plant extracts might be an alternative treatment against bee-disease-associated parasites and pathogens, in particular to replace synthetic antibiotics.
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American Foulbrood, caused by Paenibacillus larvae, is the most devastating bacterial honey bee brood disease. Finding a treatment against American Foulbrood would be a huge breakthrough in the battle against the disease. Recently, small molecule inhibitors against virulence factors have been suggested as candidates for the development of anti-virulence strategies against bacterial infections. We therefore screened an in-house library of synthetic small molecules and a library of flavonoid natural products, identifying the synthetic compound M3 and two natural, plant-derived small molecules, Acacetin and Baicalein, as putative inhibitors of the recently identified P. larvae toxin Plx2A. All three inhibitors were potent in in vitro enzyme activity assays and two compounds were shown to protect insect cells against Plx2A intoxication. However, when tested in exposure bioassays with honey bee larvae, no effect on mortality could be observed for the synthetic or the plant-derived inhibitors, thus suggesting that the pathogenesis strategies of P. larvae are likely to be too complex to be disarmed in an anti-virulence strategy aimed at a single virulence factor. Our study also underscores the importance of not only testing substances in in vitro or cell culture assays, but also testing the compounds in P. larvae-infected honey bee larvae.
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Beekeepers need sustainable control options to treat Nosema ceranae infection in colonies of western honey bees (Apis mellifera L.) they manage. Propolis is a natural product derived from plant resins and contains chemical compounds with potential antimicrobial activity against N. ceranae. Here, we determined the efficacy of propolis from A. mellifera (USA) and Tetrigona apicalis (stingless bees, Thailand) colonies as treatments for N. ceranae infection in honey bee workers. Newly emerged bees were individually fed 2 μl of 50% (w/v) sucrose solution containing 1 × 10⁵ N. ceranae spores. Following this, the infected bees were treated with 50% propolis extracted from A. mellifera or T. apicalis hives and fed in 50% sucrose solution (v/v). All bees were maintained at 34 ± 2˚C and 55 ± 5% RH. Dead bees were counted daily for 30 d to calculate survival. We also determined infection rate (# infected bees/100 bees), infectivity (number of spores per bee) and protein content in the hypopharyngeal glands and hemolymph on 7, 14, and 21 d post infection as measures of bee health. Propolis from both bee species significantly reduced bee mortality, infection rate and infectivity compared with those of untreated bees and led to significantly greater protein contents in hypopharyngeal glands and hemolymph in treated bees than in untreated ones (p< 0.0001). In conclusion, propolis from A. mellifera and T. apicalis colonies shows promise as a control against N. ceranae infection in honey bees.
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Beekeeping, performed in many parts of the world, has a very large place in the world trade market with bee products such as wax, bee venom, propolis and royal jelly, especially honey production. However, honey bee diseases are quite common and restricted the production of bee products. One of the most important of these diseases, Nosema, is caused by spores in intestinal epithelium cells of the honeybee. Nosema apis and Nosema ceranae are the factors of this disease and also common in our country. These two species can be distinguished from each other by molecular diagnostic methods. In this study, materials collected from 152 apiaries located in 13 districts of Muğla province and 62 water sources close to these apiaries. The spores were counted using Thoma lame under light microscope. DNA isolation was carried out from spore positive samples. 218MITOC FOR-REV and 321APIS FOR-REV primers were used to figure out the N. apis and N. ceranae species. After DNA sequence analysis of the obtained amplifications, it was determined that all samples formed 3 haplotypes according to studied sequences for the first time. In Muğla region, the presence of only N. ceranae as a disease agent was determined and the prevalence of the disease was detected at a rate of 71.53±6.02%. Moreover, blast analysis showed that the N. ceranae sequence detected high similarity (94-100 %) with the previously reported in Lebanon, France, Morocco and Thailand samples.
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Nosema ceranae is one of the fungal parasites of Apis mellifera. It causes physical and behavioral effects in honey bees. However, only a few studies have reported on gene expression profiling during A. mellifera infection. In this study, the transcriptome profile of mature spores at each time point of infection (5, 10, and 20 days post-infection, d.p.i.) were investigated. Based on the transcriptome and expression profile analysis, a total of 878, 952, and 981 differentially expressed genes (DEGs) (fold change ≥ 2 or ≤ −2) were identified in N. ceranae spores (NcSp) at 5 d.p.i., 10 d.p.i., and 20 d.p.i., respectively. Moreover, 70 upregulated genes and 340 downregulated genes among common DEGs (so-called common DEGs) and 166 stage-specific genes at each stage of infection were identified. The Gene Ontology (GO) analysis indicated that the DEGs and corresponding common DEGs are involved in the functions of cytosol (GO:0005829), cytoplasm (GO:0005737), and ATP binding (GO:0005524). Furthermore, the pathway analysis found that the DEGs and common DEGs are involved in metabolism, environmental information processing, and organismal systems. Four upregulated common DEGs with higher fold-change values, highly associated with spore proteins and transcription factors, were selected for validation. In addition, the stage-specific genes are highly involved in the mechanism of pre-mRNA splicing according to GO enrichment analysis; thus, three of them showed high expression at each d.p.i. and were also subjected to validation. The relative gene expression levels showed a similar tendency as the transcriptome predictions at different d.p.i., revealing that the gene expression of N. ceranae during infection may be related to the mechanism of gene transcription, protein synthesis, and structural proteins. Our data suggest that the gene expression profiling of N. ceranae at the transcriptomic level could be a reference for the monitoring of nosemosis at the genetic level.
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Nosema ceranae is a highly prevalent pathogen of Apis mellifera, which is distributed worldwide. However, there may still exist isolated areas that remain free of N. ceranae. Herein, we used molecular tools to survey the Azores to detect N. ceranae and unravel its colonisation patterns. To that end, we sampled 474 colonies from eight islands in 2014/2015 and 91 from four islands in 2020. The findings revealed that N. ceranae was not only present but also the dominant species in the Azores. In 2014/2015, N. apis was rare and N. ceranae prevalence varied between 2.7% in São Jorge and 50.7% in Pico. In 2020, N. ceranae prevalence increased significantly (p < 0.001) in Terceira and São Jorge also showing higher infection levels. The spatiotemporal patterns suggest that N. ceranae colonised the archipelago recently, and it rapidly spread across other islands, where at least two independent introductions might have occurred. Flores and Santa Maria have escaped the N. ceranae invasion, and it is remarkable that Santa Maria is also free of Varroa destructor, which makes it one of the last places in Europe where the honey bee remains naive to these two major biotic stressors.
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Nosema ceranae is an intracellular microsporidian pathogen that lives in the midgut ventricular cells of all known honey bee Apis species. We suspect that N. ceranae may also cause energetic stress in the giant honey bee because this parasite is known to disrupt nutrient absorption resulting in energetic stress in the honey bee species Apis mellifera. To understand how N. ceranae impacts the energetic stress of the giant honey bee, A. dorsata, we measured the hemolymph trehalose levels of experimentally infected giant honey bees on days three, five, seven, and fourteen post infection (p.i.). We also measured the hypopharyngeal gland protein content, the total midgut proteolytic enzyme activity, honey bee survival, infection ratio, and spore loads comparing infected and uninfected honey bees across the same time frame. Nosema ceranae-infected honey bees had significantly lowered survival, trehalose levels, hypopharyngeal gland protein content, and midgut proteolytic enzyme activity. We found an increasing level of parasitic loads and infection ratio of N. ceranae-infected bees after inoculation. Collectively, our results suggest that the giant honey bee suffers from energetic stress and limited nutrient absorption from a N. ceranae infection, which results in lowered survival in comparison to uninfected honey bees. Our findings highlight that other honey bee species besides A. mellifera are susceptible to microsporidian pathogens that they harbor, which results in negative effects on health and survival. Therefore, these pathogens might be transmitted at a community level, in the natural environment, resulting in negative health effects of multiple honey bee species.
Article
Nosema ceranae is a microsporidian parasite that causes nosema disease, an infection of the honey bee (Apis mellifera) midgut. Two pathogen-associated molecular patterns (PAMPs), chitosan and peptidoglycan, and N. ceranae spores were fed to worker bees in sucrose syrup and compared to non-inoculated and N. ceranae-inoculated bees without PAMPs. Both chitosan and peptidoglycan significantly increased bee survivorship and reduced spore numbers due to N. ceranae infection. To determine if these results were related to changes in health status, expression of the immune-related genes, hymenoptaecin and defensin2, and the stress tolerance-related gene, blue cheese, was compared to that of control bees. Compared to the inoculated control, bees with the dose of chitosan that significantly reduced N. ceranae spore numbers showed lower expression of hymenoptaecin and defensin2 early after infection, higher expression mid-infection of defensin2 and lower expression of all three genes late in infection. In contrast, higher expression of defensin2 early in the infection and all three genes late in the infection was observed with peptidoglycan treatment. Changes late in the parasite multiplication stage when mature spores would be released from ruptured host cells are less likely to have contributed to reduced spore production. Based on these results, it is concluded that feeding bees chitosan or peptidoglycan can reduce N. ceranae infection, which is at least partially related to altering the health of the bee by inducing immune and stress-related gene expression.
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Honey bees (Apis mellifera) are agriculturally important pollinators. Over the past decades, significant losses of wild and domestic bees have been reported in many parts of the world. Several biotic and abiotic factors, such as change in land use over time, intensive land management, use of pesticides, climate change, beekeeper’s management practices, lack of forage (nectar and pollen), and infection by parasites and pathogens, negatively affect the honey bee’s well-being and survival. The gut microbiota is important for honey bee growth and development, immune function, protection against pathogen invasion; moreover, a well-balanced microbiota is fundamental to support honey bee health and vigor. In fact, the structure of the bee’s intestinal bacterial community can become an indicator of the honey bee’s health status. Lactic acid bacteria are normal inhabitants of the gastrointestinal tract of many insects, and their presence in the honey bee intestinal tract has been consistently reported in the literature. In the first section of this review, recent scientific advances in the use of LABs as probiotic supplements in the diet of honey bees are summarized and discussed. The second section discusses some of the mechanisms by which LABs carry out their antimicrobial activity against pathogens. Afterward, individual paragraphs are dedicated to Chalkbrood, American foulbrood, European foulbrood, Nosemosis, and Varroosis as well as to the potentiality of LABs for their biological control.
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«Сучасне бджільництво: проблеми, досвід, нові технології» : збірник матеріалів науково-практичної конференції з міжнародною участю (20 серпня 2021 року) [Електронний ресурс] / Постоєнко В., Литвиненко О., Адамчук Л., Акименко Л. Київ: ННЦ «Інститут бджільництва імені П.І. Прокоповича», 2021. 56 с. У збірнику висвітлено результати актуальних напрямів наукових досліджень у бджільництві. Авторами матеріалів є здобувачі наукових ступенів та викладачі навчальних закладів І–ІV рівнів акредитації, наукові співробітники.
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Nosema ceranae is a unicellular microsporidian causing ventricular cell lysis in host Apis spe-cies. We hypothesized that the gut microbiota of honey bees, A. cerana, A. dorsata, A. florea, and A. mellifera, is disrupted by N. ceranae infection. Correspondingly, we investigated the impact of N. ceranae infection on gut populations of Bifidobacterium sp. and Apilactobacillus kunkeei in the selected Apis species. The bacteria populations were compared using a cul-ture-dependent method and employing 16S rRNA gene sequencing between bees infected with 2.0 􀀁 105N. ceranae spores and those remaining uninfected. The number of N. ceranae spores per bee and the ratio of infected gut cells to uninfected cells were measured at five and ten days post infection (p.i.). N. ceranae spore load at ten days p.i. was significantly greater than at five days p.i. and was varied with species’ body size. For each of the four Apis species, N. ceranae treated bees had lower survival than did the control bees. Moreover, A. florae had the largest infection ratio of all the species. Across all Apis species, N. ceranae infected individuals had significantly lower mean numbers of Bifidobacterium sp. and A. kun-keei than did uninfected ones. Among infected bees, the average number of both bacteria was significantly greatest in A. dorsata and lowest in A. cerana. Overall, N. ceranae infection was associated with histopathological damage and also with lower populations of Bifidobacterium sp. and A. kunkeei in the midguts of the tested honey bee species.
Preprint
Managed and wild insect pollinators play a key role in ensuring that mankind is adequately supplied with food. Among the pollinating insects, the managed Western honey bee providing about 90% of commercial pollination is of special importance. Hence, diseases as well as disease causing pathogens and parasites that threaten honey bees, have become the focus of many research studies. The ectoparasitic mite Varroa destructor together with deformed wing virus (DWV) vectored by the mite have been identified as the main contributors to colony losses, while the role of the microsporidium Nosema ceranae in colony losses is still controversially discussed. In an attempt to solve this controversy, we statistically analyzed a unique data set on honey bee colony health comprising data on mite infestation levels, Nosema spp. infections and winter losses continuously collected over 15 years. We used various statistical methods to investigate the relationship between colony mortality and the two pathogens, V. destructor and N. ceranae . Our multivariate statistical analysis confirmed that V. destructor is the major cause of colony winter losses. When using cumulative data sets, we also found a significant relationship between N. ceranae infections and colony losses. However, determining the effect size revealed that this statistical significance was of low biological relevance, because the deleterious effects of N. ceranae infection are normally masked by the more severe effects of V. destructor on colony health and therefore only detectable in the few colonies that are not infested with mites or are infested at low levels.
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The epidemiology of Nosema spp. in honey bees, Apis mellifera , may be affected by winter conditions as cold temperatures and differing wintering methods (indoor and outdoor) provide varying levels of temperature stress and defecation flight opportunities. Across the Canadian Prairies, including Alberta, the length and severity of winter vary among geographic locations. This study investigates the seasonal pattern of Nosema abundance in two Alberta locations using indoor and outdoor wintering methods and its impact on bee population, survival, and commercial viability. This study found that N . ceranae had a distinct seasonal pattern in Alberta, with high spore abundance in spring, declining to low levels in the summer and fall. The results showed that fall Nosema monitoring might not be the best indicator of treatment needs or future colony health outcomes. There was no clear pattern for differences in N . ceranae abundance by location or wintering method. However, wintering method affected survival with colonies wintered indoors having lower mortality and more rapid spring population build-up than outdoor-wintered colonies. The results suggest that the existing Nosema threshold should be reinvestigated with wintering method in mind to provide more favorable outcomes for beekeepers. Average Nosema abundance in the spring was a significant predictor of end-of-study winter colony mortality, highlighting the importance of spring Nosema monitoring and treatments.
Article
Aim of study: The aim of this study was to assess the impact of the mite control strategies combined with nutritional management on honey bee colony dynamics and survival during winter, the following spring, and summer. Area of study: Santa Fe province in central Argentina. Material and methods: We set two apiaries with 40 colonies each and fed one apiary with high fructose corn syrup (HFCS) and the other with sucrose syrup (SS). Within each apiary, we treated half the colonies against Varroa mites and half of these treated colonies also received a pollen patty. The other half of the colonies remained untreated and did not received pollen patties. All colonies were sampled for Varroa infestation level, Nosema ceranae abundance and colony strength seven times during a year (from summer 2016 to autumn 2017). We computed autumn mite invasion and colony losses at each sampling time. Main results: Colonies fed with HFCS had more brood cells during the study that those fed with SS and treated colonies had fewer adult bees and Varroa infestation than untreated colonies. No significant effect of the protein supplementation was observed on any of the response variables. , SS colonies from all groups had significantly more mites drop counts than HFCS colonies. Research highlights: Considering that a reduced frequency of application is desirable, our results suggested that nutrition management could enhance chemical treatment effectiveness since honey bees might profit from improved nutrition. However, a better understanding of the nutritional requirements of the colonies under field conditions is needed.
Chapter
This chapter presents the main features of the biology of Apis mellifera , viral diseases, bacterial diseases, parasites of the honey bee, and in particular the mite Varroa destructor , pests and predators of the hives, and finally intoxication of the honey bee colonies. Honey bees are classified in the family Apidae, which includes the orchid bees, bumblebees, and stingless bees. Apis mellifera is a social insect with individual features and a complex social organization. The digestive tract allows breakdown of foods and absorption of nutrients. The nervous system of the honey bee is complex and allows for environmental adaptation. Destruction of infected colonies is a sanitary and reliable method to control American foulbrood. Chronic bee paralysis RNA virus frequently persists as a covert infection in honey bee colonies throughout the year. Acute Bee Paralysis Virus is a single-stranded RNA Discitroviridae virus . Kashmir Bee Virus is a single-stranded RNA Discitroviridae virus .
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The honey bee is economically significant insect and plays an important role in the pollination of various plants. With regard to the widespread use of pesticides in agricultural lands, honey bees, as non-target and useful insect, inadvertently contact these chemicals. Thus, in order to evaluate the effects of some pesticides, the toxicity of three insecticides from different chemical classes including imidacloprid (0.16 mg a.i./l), ethion (79.47 mg a.i./l), and hexaflumuron (500 mg a.i./l) on detoxifying enzymes of worker honey bees and mortality of immature bees was investigated. These chemicals were selected because they are used globally and ingested by honey bees. The sub-lethal concentration of imidacloprid reduced the activity of the acetylcholinesterase (AChE) and glutathione S-transferase (GST). Exposure to the sub-lethal concentrations of the ethion reduced the esterase (EST) activities in treated honey bees. Exposure of honey bee larvae to imidacloprid (0.16 mg a.i./l), ethion (79.47 mg a.i./l), and hexaflumuron (500 mg a.i./l) increased the mortality of the treated group compared to untreated controls, but this difference was not statistically significant. Our results indicate that imidacloprid and ethion disrupt the physiology of honey bees, thereby reducing the efficiency of this beneficial pollinator. Also, it is important that additional studies be performed to investigate the sub-lethal effects of pesticides on larval development.
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Flowers can be transmission platforms for parasites that impact bee health, yet bees share floral resources with other pollinator taxa, such as flies, that could be hosts or non-host vectors (i.e., mechanical vectors) of parasites. Here, we assessed whether the fecal-orally transmitted gut parasite of bees, Crithidia bombi , can infect Eristalis tenax flower flies. We also investigated the potential for two confirmed solitary bee hosts of C. bombi , Osmia lignaria and Megachile rotundata , as well as two flower fly species, Eristalis arbustorum and E. tenax , to transmit the parasite at flowers. We found that C. bombi did not replicate (i.e., cause an active infection) in E. tenax flies. However, 93% of inoculated flies defecated live C. bombi in their first fecal event, and all contaminated fecal events contained C. bombi at concentrations sufficient to infect bumble bees. Flies and bees defecated inside the corolla (flower) more frequently than other plant locations, and flies defecated at volumes comparable to or greater than bees. Our results demonstrate that Eristalis flower flies are not hosts of C. bombi , but they may be mechanical vectors of this parasite at flowers. Thus, flower flies may amplify or dilute C. bombi in bee communities.
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Polymerase chain reaction (PCR), restriction fragment length polymorphism (RFLP) analysis and microscopy were used to test 307 adult bee and 37 honey samples collected in Australia for the presence of two microsporidia, Nosema ceranae and Nosema apis. N. ceranae was detected in samples from 4 states (Queensland, New South Wales, Victoria and South Australia) and was most commonly found in samples from Queensland where 28 (33.7%) of 83 samples were positive. New South Wales had the second highest prevalence with 15 (15.8%) of 95 samples positive. South Australia and Victoria had 4 (16%) of 25 and 2 (4.5%) of 44 samples positive respectively. N. ceranae was not detected in samples from Western Australia and Tasmania. N. apis was detected in samples from all states. Three honey samples (8.1%) were PCR positive for N. ceranae. These positive honey samples originated from beekeepers in Queensland. Six imported honey samples tested were negative for both Nosema spp.
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In this paper, we review the main thresholds that can infl uence the population dynamics of host–parasite relationships. We start by considering the thresholds that have infl u-enced the conceptualisation of theoretical epidemiology. The most common threshold involving parasites is the host population invasion threshold, but persistence and infec-tion thresholds are also important. We recap how the existence of the invasion thresh-old is linked to the nature of the transmission term in theoretical studies. We examine some of the main thresholds that can affect host population dynamics including the Allee effect and then relate these to parasite thresholds, as a way to assess the dynamic consequences of the interplay between host and parasite thresholds on the fi nal out-come of the system. We propose that overlooking the existence of parasite and host thresholds can have important detrimental consequences in major domains of applied ecology, including in epidemiology, conservation biology and biological control.
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Parasites are dependent on their hosts for energy to reproduce and can exert a significant nutritional stress on them. Energetic demand placed on the host is especially high in cases where the parasite-host complex is less co-evolved. The higher virulence of the newly discovered honeybee pathogen, Nosema ceranae, which causes a higher mortality in its new host Apis mellifera, might be based on a similar mechanism. Using Proboscis Extension Response and feeding experiments, we show that bees infected with N. ceranae have a higher hunger level that leads to a lower survival. Significantly, we also demonstrate that the survival of infected bees fed ad libitum is not different from that of uninfected bees. These results demonstrate that energetic stress is the probable cause of the shortened life span observed in infected bees. We argue that energetic stress can lead to the precocious and risky foraging observed in Nosema infected bees and discuss its relevance to colony collapse syndrome. The significance of energetic stress as a general mechanism by which infectious diseases influence host behavior and physiology is discussed.
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The degree to which a disease evolves to be virulent depends, in part, on whether the pathogen is transmitted horizontally or vertically. Eusocial insect colonies present a special case since the fitness of the pathogen depends not only on the ability to infect and spread between individuals within a colony, but also on the ability to spread to new individuals in other colonies. In honey bees, intercolony transmission of pathogens occurs horizontally (by drifting or robbing) and vertically (through swarming). Vertical transmission is likely the most important route of pathogen infection of new colonies. Theory predicts that this should generally select for benign host-parasite relationships. Indeed, most honey bee diseases exhibit low virulence. The only major exception is American foulbrood (AFB). In light of current ideas in evolutionary cpidemiology, we discuss the implications of horizontal and vertical pathogen transmission for virulence of AFB and other honey bee diseases.
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The economically most important honey bee species, Apis mellifera, was formerly considered to be parasitized by one microsporidian, Nosema apis. Recently, [Higes, M., Martín, R., Meana, A., 2006. Nosema ceranae, a new microsporidian parasite in honeybees in Europe, J. Invertebr. Pathol. 92, 93-95] and [Huang, W.-F., Jiang, J.-H., Chen, Y.-W., Wang, C.-H., 2007. A Nosema ceranae isolate from the honeybee Apis mellifera. Apidologie 38, 30-37] used 16S (SSU) rRNA gene sequences to demonstrate the presence of Nosema ceranae in A. mellifera from Spain and Taiwan, respectively. We developed a rapid method to differentiate between N. apis and N. ceranae based on PCR-RFLPs of partial SSU rRNA. The reliability of the method was confirmed by sequencing 29 isolates from across the world (N =9 isolates gave N. apis RFLPs and sequences, N =20 isolates gave N. ceranae RFLPs and sequences; 100% correct classification). We then employed the method to analyze N =115 isolates from across the world. Our data, combined with N =36 additional published sequences demonstrate that (i) N. ceranae most likely jumped host to A. mellifera, probably within the last decade, (ii) that host colonies and individuals may be co-infected by both microsporidia species, and that (iii) N. ceranae is now a parasite of A. mellifera across most of the world. The rapid, long-distance dispersal of N. ceranae is likely due to transport of infected honey bees by commercial or hobbyist beekeepers. We discuss the implications of this emergent pathogen for worldwide beekeeping.
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Nosema ceranae, a microsporidian formerly regarded as confined to its Asiatic host Apis cerana, has recently been shown to parasitise Apis mellifera and to have spread throughout most of the world in the past few years. Using a temporal sequence of N = 28 Nosema isolates from Finland from 1986–2006, we now find (i) that N. ceranae has been present in Europe since at least 1998 and (ii) that it has increased in frequency across this time period relative to Nosema apis, possibly leading to higher mean spore loads per bee. We then present results of a single laboratory infection experiment in which we directly compare the virulence of N. apis with N. ceranae. Though lacking replication, our results suggest (iii) that both parasites build up to equal numbers per bee by day 14 post infection but that (iv) N. ceranae induces significantly higher mortality relative to N. apis.
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Microsporidiosis (nosema disease) of the honeybee, Apis mellifera, has spread worldwide and caused heavy economic losses in apiculture. We obtained a spore isolate from worker ventriculi of A. mellifera colonies kept on the campus of National Taiwan University and sequenced the ribosomal genes. The entire length of the ribosomal DNA is about 3828 bp and the organization is similar to that of Nosema apis. However, the SSUrRNA, ITS, and LSUrRNA sequences have comparatively low identities with those of N. apis (92, 52, and 89%, respectively) and the SSUrRNA has a 99% identity with Nosema ceranae. These results indicate that this isolate is not N. apis, but N. ceranae. Moreover, the morphological characteristics are identical to those of N. ceranae. These results show that nosema disease of the honeybee, A. mellifera, may not be caused solely by the infection of N. apis.
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Recent steep declines in honey bee health have severely impacted the beekeeping industry, presenting new risks for agricultural commodities that depend on insect pollination. Honey bee declines could reflect increased pressures from parasites and pathogens. The incidence of the microsporidian pathogen Nosema ceranae has increased significantly in the past decade. Here we present a draft assembly (7.86 MB) of the N. ceranae genome derived from pyrosequence data, including initial gene models and genomic comparisons with other members of this highly derived fungal lineage. N. ceranae has a strongly AT-biased genome (74% A+T) and a diversity of repetitive elements, complicating the assembly. Of 2,614 predicted protein-coding sequences, we conservatively estimate that 1,366 have homologs in the microsporidian Encephalitozoon cuniculi, the most closely related published genome sequence. We identify genes conserved among microsporidia that lack clear homology outside this group, which are of special interest as potential virulence factors in this group of obligate parasites. A substantial fraction of the diminutive N. ceranae proteome consists of novel and transposable-element proteins. For a majority of well-supported gene models, a conserved sense-strand motif can be found within 15 bases upstream of the start codon; a previously uncharacterized version of this motif is also present in E. cuniculi. These comparisons provide insight into the architecture, regulation, and evolution of microsporidian genomes, and will drive investigations into honey bee-Nosema interactions.
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The biological cycle of Nosema spp. in honeybees depends on temperature. When expressed as total spore counts per day after infection, the biotic potentials of Nosema apis and N. ceranae at 33°C were similar, but a higher proportion of immature stages of N. ceranae than of N. apis were seen. At 25 and 37°C, the biotic potential of N. ceranae was higher than that of N. apis. The better adaptation of N. ceranae to complete its endogenous cycle at different temperatures clearly supports the observation of the different epidemiological patterns.
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Some microsporidian parasites belonging to the genus Nosema infect bees. Previous phylogenies of these parasites have produced alternative, conflicting relationships. We analyzed separately, and in combination, large and small subunit ribosomal DNA sequences of Nosema species infecting bees under neighbor-joining, maximum parsimony, maximum likelihood, and Bayesian frameworks. We observed a sister relationship between Nosema ceranae and Nosema bombi, with Nosema apis as a basal member to this group. When compared to their respective hosts (Apis cerana, Bombus spp., and A. mellifera), 2 plausible evolutionary scenarios emerged. The first hypothesis involves a common ancestor of N. bombi host-switching from a historical Bombus lineage to A. cerana. The second suggests an ancestral N. ceranae host-switching to a species of Bombus. The reported events offer insight into the evolutionary history of these organisms and may explain host specificity and virulence of Nosema in these economically important insects.
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We have taken samples of honey from individual beekeepers (N = 64), and of domestic (N = 35) and imported honey (N = 15) retailed in supermarkets in several sub-Saharan countries and cultivated these samples for Paenibacillus larvae subsp. larvae Heyndrickx et al. causing American foulbrood in honey bee colonies. The results are compared with samples of similar backgrounds and treated the same way but collected in Sweden (N = 35). No P. larvae subsp. larvae spores were found in any honey produced in Africa south of the Sahara although honey imported into this region frequently contains the pathogen. Swedish honey frequently contains P. larvae subsp. larvae spores although the general level of visibly infected bee colonies is low (roughly 0.5%). The results suggest that large parts of Africa may be free from American foulbrood. Behavioral studies (hygienic behavior) on Apis mellifera subsp. scutellata Lepeletier in Zimbabwe suggest that hygienic behavior of African bees could influence the apparent low level, or even absence of American foulbrood in large parts of Africa.
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This revision of the classification of unicellular eukaryotes updates that of Levine et al. (1980) for the protozoa and expands it to include other protists. Whereas the previous revision was primarily to incorporate the results of ultrastructural studies, this revision incorporates results from both ultrastructural research since 1980 and molecular phylogenetic studies. We propose a scheme that is based on nameless ranked systematics. The vocabulary of the taxonomy is updated, particularly to clarify the naming of groups that have been repositioned. We recognize six clusters of eukaryotes that may represent the basic groupings similar to traditional "kingdoms." The multicellular lineages emerged from within monophyletic protist lineages: animals and fungi from Opisthokonta, plants from Archaeplastida, and brown algae from Stramenopiles.
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Twelve samples of adult honey bees from different regions of Spain from colonies with clear signs of population depletion, positive to microsporidian spores using light microscopy (1% of total positive samples analysed), were selected for molecular diagnosis. PCR specific primers for a region of the 16S rRNA gene of Microsporidia were developed and the PCR products were sequenced and compared to GenBank entries. The sequenced products of 11 out of the 12 samples were identical to the corresponding Nosema ceranae sequence. This is the first report of N. ceranae in colonies of Apis mellifera in Europe. The suggested link of the infections to clinical disease symptoms makes imperative a study of the virulence of N. ceranae in European races of honey bees.
Article
Investigations of queen, worker and male bumble bees (Bombus terrestris) showed that all individuals became infected with Nosema bombi. Infections were found in Malpighian tubules, thorax muscles, fat body tissue and nerve tissue, including the brain. Ultrastructural studies revealed thin walled emptied spores in host cell cytoplasm interpreted as autoinfective spores, besides normal spores (environmental spores) intended for parasite transmission between hosts. The nucleotide sequence of the gene coding for the small subunit rRNA (SSU-rRNA) from Microsporidia isolated from B. terrestris, B. lucorum, and B. hortorum were identical, providing evidence that N. bombi infects multiple hosts. The sequence presented here (GenBank Accession no AY008373) is different from an earlier submission to GenBank (Accession no U26158) of a partial sequence of the same gene based on material collected from B. terrestris. It still remains to be investigated if there is species diversity among Microsporidia found in bumble bees.
Article
Spodoptera exempta larvae were reared on semisynthetic maize diet. Pathogenicity studies were undertaken on first- to fifth-instar larvae fed a high dosage of Nosema necatrix spores. Larvae from the earlier instars were most susceptible to the microsporidan and also developed bacteriosis. A cytoplasmic polyhedrosis virus (CPV) was evident in some infected larvae but not in controls. The development of N. necatrix is redescribed using the light microscope. A disporoblastic life cycle was evident at 25°C and both a disporoblastic and an octosporoblastic life cycle at 20°C. The implications of the occurrence of bacteriosis and CPV and the possible biological significance of the two sporogonic sequences are discussed. The taxonomic position of N.necatrix is reviewed and, after comparison with existing species of the genera Nosema and Parathelohania, it is placed in the new genus Vairimorpha. The implications of polymorphism are discussed in relation to the classification of the Microsporida.
Article
The morphology and developmental cycles of two new species of Microsporidia parasitic in the fat bodies of larvae of armyworms (Pseudaletia) are described. They are named Nosema necatrix and Thelohania diazoma. Preliminary tests indicate that the parasites are pathogenic.
Article
Intracellular germination of Nosema apis spores is shown in TEM preparations of infected honey bee (Apis mellifera) ventricular cells. A series of observations at different times post-infection provides support for a hypothesis that could explain the rapid intercellular spread of the parasite. It is suggested that the first spores produced often germinate and spread the parasite within the epithelium, whereas intact and durable spores are produced later in infected cells when they become more crowded with parasites.
Article
Based on light microscopic and ultrastructural characteristics as well as on the nucleotide sequence of the small subunit ribosomal RNA coding region, the microsporidium Nosema ceranae n. sp., a parasite of the Asian honey bee Apis cerana is described. Merogonial stages and sporonts are diplokaryotic. Merozoites are mostly formed by cytoplasmic fission in quadrinucleate meronts and the number of merogonial cycles may vary. The sporogony is disporoblastic. The living mature spore is ovocylindrical, straight to slightly curved and measures 4.7 × 2.7 μm whereas fixed and stained spores measure 3.6 × 1.7 μm. The polar filament is isofilar with a diameter of 96–102 nm and is arranged in 20–23 coils in the posterior and mid-part of the spore. In the anterior part of the polaroplast there are closely packed approximately 11 nm thick lamellae. The lamellae of the posterior polaroplast are thicker and less regular. In the posterior part of the mature spore a well fixed posterior body interpreted as a posterosome was often observed. Phylogenetic analysis, based on the sequence of the small subunit ribosomal RNA, places Nosema ceranae in the Nosema clade, as defined by Nosema bombycis, the type species of the Nosema genus.
Article
Many factors may influence the division of labor of worker Apis mellifera L. in the colony. Nosema disease, Nosema apis Zander, can alter drastically the age-duty sequence. Nosema-infected bees apparently are physiologically older than healthy bees of the same age and they started guarding. foraging. dancing, and orientation flying earlier than healthy bees. Bees heavily infected with nosema (an average of 131.8×104spores per milliliter per bee) still can perform foraging duties. Nosema-infected bees that attended and/or fed the queen were statistically fewer than healthy bees. This change in feeding behavior of infected worker bees may be the result of atrophy of their hypopharyngeal glands and may contribute to the queen’s frequent escape from nosema infection.
Article
Infection of the adult worker honeybee with Nosema apis reduces or obviates brood feeding and causes her to commence foraging earlier than a healthy bee. The length of foraging activity and the total length of life of infected bees is reduced. In colonies infected with N. apis the rate of brood rearing is severely depressed during April, May and June, the degree of depression being proportional to the percentage infection. Infection decreases during July, August and September, and consequently the rate of brood rearing increases, but the resulting addition in foraging population is usually too late to increase the honey crop.
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Vairimorpha necatrix infected adipose ceiis of the fat body organ of Trichoplusia ni larvae 3–31/2 days after exposure of the larvae to infective spores. During the subsequent 4–6 days, the parasitized adipose cells were hypertrophied in part due to the rapid propagation of V. necatrix schizonts. A calcium-sensitive tubule network developed at the interface of the schizonts and the adipose ceil cytoplasm. The paired nuclei of V. necatrix have pores at the nuclear interface. The pores for each nucleus at this interface are spatially positioned so that they are in conjunction; hence, there is the potential for a channel system between the 2 nuclei.
Article
The proportion of honey-bees infected with Nosema apis (Zander) declines in summer as the old infected bees die, for they cease to transmit their infection to the newly emerged individuals during the flying season. N. apis spores survive the summer on combs contaminated with infected faeces during the preceding winter. Although bees clean the combs during the summer, all infected material is not removed, and even well-used brood comb, which has been repeatedly cleaned by bees, can carry infection. Only a few bees may contract infection in the autumn from these faeces, but they join the winter cluster and initiate the next outbreak of the disease. Transferring a colony on to clean comb early in the spring or summer removes the source of the disease, and it then disappears when all the old infected bees die. Old broodless comb can be sterilized quite simply by fumigation for a few days with the vapours of formalin or glacial acetic acid. Acetic acid is preferable, because it does not poison any honey or pollen in the combs. Formaldehyde can safely be used only with empty combs. The autumn is the best time for treating colonies chemotherapeutically, because the combs are then cleanest and the few bees which are infected can be cured during the winter. The drug can be incorporated in the syrup normally fed to colonies in autumn, and there is no risk of seriously contaminating subsequent honey crops. However, such treatment cannot eliminate the disease because sufficient spores remain on the combs for the disease to start again when the drug supplied in the winter stores is exhausted.
Article
Nosema ceranae, a microsporidian parasite originally described from Apis cerana, has been found to infect Apis melllifera and is highly pathogenic to its new host. In the present study, data on the ultrastructure of N. ceranae, presence of N. ceranae-specific nucleic acid in host tissues, and phylogenetic relationships with other microsporidia species are described. The ultrastructural features indicate that N. ceranae possesses all of the characteristics of the genus Nosema. Spores of N. ceranae measured approximately 4.4 × 2.2 μm on fresh smears. The number of coils of the polar filament inside spores was 18–21. Polymerase chain reaction (PCR) signals specific for N. ceranae were detected not only in the primary infection site, the midgut, but also in the tissues of hypopharyngeal glands, salivary glands, Malpighian tubules, and fat body. The detection rate and intensity of PCR signals in the fat body were relatively low compared with other examined tissues. Maximum parsimony analysis of the small subunit rRNA gene sequences showed that N. ceranae appeared to be more closely related to the wasp parasite, Nosema vespula, than to N. apis, a parasite infecting the same host.
Book
The Honey Bee. Viruses. Bacteria. Fungi. Protozoa and Microspora. Parasitic Mites. Insect and Nemtode Parasites. Disorders of Uncertain Orgin and Non-Infectious Diseases. The Treatment of Bee Diseases. Conclusions. References. Subject Index. Index.
Article
In recent years, honeybees (Apis mellifera) have been strangely disappearing from their hives, and strong colonies have suddenly become weak and died. The precise aetiology underlying the disappearance of the bees remains a mystery. However, during the same period, Nosema ceranae, a microsporidium of the Asian bee Apis cerana, seems to have colonized A. mellifera, and it's now frequently detected all over the world in both healthy and weak honeybee colonies. For first time, we show that natural N. ceranae infection can cause the sudden collapse of bee colonies, establishing a direct correlation between N. ceranae infection and the death of honeybee colonies under field conditions. Signs of colony weakness were not evident until the queen could no longer replace the loss of the infected bees. The long asymptomatic incubation period can explain the absence of evident symptoms prior to colony collapse. Furthermore, our results demonstrate that healthy colonies near to an infected one can also become infected, and that N. ceranae infection can be controlled with a specific antibiotic, fumagillin. Moreover, the administration of 120 mg of fumagillin has proven to eliminate the infection, but it cannot avoid reinfection after 6 months. We provide Koch's postulates between N. ceranae infection and a syndrome with a long incubation period involving continuous death of adult bees, non-stop brood rearing by the bees and colony loss in winter or early spring despite the presence of sufficient remaining pollen and honey.
Article
Inbred bees (Apis mellifera ligustica) from seven different colonies were dosed individually with spores of Nosema apis and kept in cages. Longevity and spores carried at the time of death were recorded for each bee. The experiment was repeated on three different dates. Control bee longevity varied with experiment date, although the pattern of this resp