Article

Some Abiotic Factors Affecting the Survival of the Cat Flea, Ctenocephalides felis (Siphonaptera: Pulicidae)

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Abstract

Some abiotic environmental factors influencing the survival of the cat flea, Ctenocephalides felis (Bouché), in semi-arid and temperature climates were studied. Pupae survived outdoors throughout most of the year except July and August, when temperatures often exceeded 35°C. As temperatures increased, the time required to kill larvae exposed to 12 and 33% relative humidity (RH) decreased. At 27°C, 16-h exposures to 12% RH and 24-h exposures to 33% RH provided 100 and 97% mortality, respectively. Larvae survived only when the RH was >50% for several consecutive days or the microhabitats provided substantially higher than ambient humidity. Soil moistures of 1 to 10% permitted larval development even when larvae were held at 12 ± 2% RH. Soil moistures from 20 to 50% were deleterious. Emerged and preemerged adults survived short exposures to low temperatures but were killed by 10-day or 5-day exposures at 3 and −1°C, respectively. Exposures to 3°C for 5 days killed all immature stages.

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... The chosen response variables were required to be within the environmental thresholds for C. felis survival. Namely, temperatures between 3-35 °C with 70-95% humidity and high precipitation levels (> 500 mm yearly) [17,18]. Receiver operating characteristics (ROC) curves were assessed, where the area under the curve (AUC) was used to evaluate the accuracy of the resulting model. ...
... bom.gov.au/iwk/clima te_zones /map_1.shtml ) [17,18]. The Clade 'Darwin' model revealed that the range of haplotype h3 is along the northern coastal environments. ...
... It is known that flea infestations are mostly absent in the Australian inland communities as drought conditions are too harsh for flea survival [39]. As C. felis development and survival is highly dependent on moist environments, distribution is most likely to be found in those regions [17]. As moist regions are becoming further restricted to coastlines in the future, the model suggests that there will be an increase in flea populations in these areas. ...
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Background Bioclimatic variables play an integral part in the life-cycle of Ctenocephalides felis, the most common flea found on companion animals. It is essential that we understand the effects of climate on C. felis distribution as fleas are a major veterinary and public health concern. This study investigated the current distribution of C. felis in Australia and future projections based on climate modelling. Results Typing of C. felis was undertaken using the cytochrome c oxidase subunit 1 (cox1) mitochondrial DNA (mtDNA) region and current distribution of haplotypes was mapped by Maximum Entropy (Maxent) niche modelling. All C. felis haplotypes have been predicted to persist in environments along the eastern and southern coastlines of Australia and distinct ecological niches were observed for two C. felis haplogroups. Clade ‘Cairns’ haplogroup thrives under the northern coastal tropical conditions whilst Clade ‘Sydney’ haplogroup persists in temperate climates along the eastern and southern coasts. The model was then used to predict areas that are projected to have suitable climatic conditions for these haplogroups in 2050 and 2070 under the Intergovernmental Panel on Climate Change (IPCC) climate change scenarios. Under all IPCC Representative Concentration Pathways (RCP) climate change scenarios, the geographical range of all haplotypes was reduced by 5.59–42.21% in 2050 and 27.08–58.82% by 2070. The ranges of all clades were predicted to shift south along the eastern coastline. Conclusions As future temperatures exceed critical threshold temperatures for C. felis development in the northern tropical areas, Clade ‘Cairns’ haplogroup is predicted to shift south along the coastline and possibly outcompete the temperate haplogroup in these areas. If C. felis haplogroups possess distinct climatic niches it suggests a potential for these to be biologically distinct and have differing developmental rates and vector capabilities.
... However, suitable outdoor sites are even rarer. Silverman and Rust ( 1983 ) found that larvae only survived outdoors when the RH was greater than 50% for several consecutive days or microhabitats provided higher RH. In summary, outdoor habitats that promote C. felis development provide a RH of greater than 50%, have a soil moisture level of less than 20%, and protect against temperatures above 35 °C and below 4°C. ...
... The survival of newly emerged fleas depends greatly upon temperature and humidity. In moisture-saturated air, 62% of adult C. felis survived for 62 days, while in cool, dry air, only 10% survived for 20 days (Silverman and Rust, 1983 ). Only 5% of C. felis maintained at 22.5°C and 60% RH survived for 12 days (Dryden, 1988). ...
... While some flea species survive the winter as pupae or adults off the host (Humphries, 1968;Schelhass and Larson, 1989), no life stage of C. felis can survive for 10 days at 3°C or for 5 days at -1 °C (Silverman and Rust, 1983). The explanation for yearly recurrences may be found in the extremely wide host range for C. felis. ...
Article
Control failures and recurrences of infestation of dogs, cats and their home environment with the cat flea, Ctenocephalides felis felis are common. Attempts to control these infestations are often impaired by an inadequate understanding of the interaction of the cat flea with its hosts and environment. This review presents information on the medical and veterinary importance of the cat flea and discusses recent information on the environmental and host factors that effect its development and survival. Additionally, information is presented on the use and effectiveness of various insecticides and insect growth regulators against the four life stages.
... The survival of C. felis during winters in northern temperate climates is intriguing, because of the apparent inability of any life stage to survive exposure to temperatures below −1 • C for more than five days (152). Survival and maintenance of C. felis populations is likely to occur through several mechanisms: (a) the presence of adults on domestic and feral dogs and cats; (b) the presence of adults on urbanized small wild animals (such as raccoons and opossums); (c) delayed development of immature stages in freeze-protected underground dens of wildlife; and (d) delayed development of pupae and emergence of adults in the in-home environment. ...
... The time required for eggs to hatch increases from 1.5 to 6.0 days as temperature decreases from 32 to 13 • C (154). Exposure to 3 • C for 1 day kills 65% of the eggs, and longer exposures provide complete kill (152). LARVA Cat flea larvae have a minimal nutritional requirement of dried blood (used here as equivalent to adult flea feces) to develop. ...
... The rate of larval development is temperature dependent. Exposures at 3 • C for 5 days and 8 • C for 20 days were lethal to larvae (152). At 13 • C and 75% RH, about 50% of the larvae pupate within 34 days. ...
Article
The cat flea, Ctenocephalides felis felis, is the most important ectoparasite of domestic cats and dogs worldwide. In addition to its annoyance to pets and humans, C. felis felis is responsible for flea bite allergy dermatitis and the transmission of dog tapeworm. The abiotic and biotic factors that affect the development of immature stages are reviewed with special emphasis given to those aspects directly affecting control. Factors influencing host selection and feeding by adults are summarized. Recent studies concerning mating and oviposition, especially as they impact the likelihood of survival by immatures, are discussed. There has been an increase in the number of reports of insecticide resistance in the past ten years. Greater attention has been placed on disrupting larval development in modern IPM programs. The immature stages of the cat flea are extremely susceptible to environmental factors such as temperature and relative humidity and insect growth regulators (IGRs). In recent years, the control of cat fleas has increasingly relied on the use of IGRs applied to the host or to the indoor environment. Finally, we discuss advances in pesticide chemistry that provide tools for better control of adult fleas on the host.
... The effect of temperature and humidity on the survival has been studied in only a few ßea species. Air temperature inßuences the developmental time and emergence of the rat ßea, X cheopis, and the cat ßea, Ctenocephalides felis Bouche, 1835 (Margalit and Shulov 1972, Silverman and Rust 1983, Metzger and Rust 1997. In the cat ßea, the pre-emerged adult stage is capable in surviving prolonged periods during the absence of hosts or during unfavorable environmental conditions such as winter or midsummer. ...
... Larvae, in contrast, cannot close their spiracles, and thus are extremely sensitive to low humidity (Roberts and Janovy 1996), although Bahmanyar and Cavanaugh (1976) demonstrated that X. cheopis can complete its life cycle at 60% and Xenopsylla brasiliensis Baker, 1904 at 51% RH. Bruce (1948) reported that the survival of cat ßea larvae was relatively high at 21Ð32ЊC and declined at higher temperatures whereas no larval survival occurred Ͻ45 or Ͼ95% RH. Larvae and pupae of the cat ßea did not survive at air temperatures Ͼ35ЊC even at the optimal relative humidity (Silverman et al. 1981, Silverman andRust 1983). Outdoor survival of the cat ßea larvae was greatest at moderate temperatures and humidities (Kern et al. 1999). ...
... Surprisingly, we did not Þnd any signiÞcant inßuence of temperature on the survival of either species except that maximal survival time of larvae at intermediate (55Ð75%) humidity was higher at 25 than at 28ЊC in both species. Temperature has been repeatedly reported to have a profound effect on immature ßea survival (e.g., Bruce 1948, Silverman and Rust 1983, Kern et al. 1999. However, the absence of temperature effect in this study could be attributed to the narrow range of temperatures tested. ...
Article
The survival of immatture fleas at 25 and 28 degrees C and 40, 55, 75, and 92% RH was studied to test the hypothesis that the difference in microclimatic preferences determines habitat distribution of Xenopsylla conformis Wagner, 1903 and Xenopsylla ramesis Rothschild, 1904. Survival of X. conformis eggs did not depend on either temperature or humidity or both, whereas eggs of X. ramesis survived significantly less at 40% RH than at higher humidities. No larva of either species survived at 40% RH at either temperature. Larval survival of both species at both temperature regimes was significantly lower at 55% humidity than at higher humidities. Maximal survival time of larvae that died before pupation depended on both temperature and humidity in both species. Change of humidity during early stages of the life cycle (from egg to larva) increased the maximal survival time in X. conformis larvae but decreased that in X. ramesis larvae. Pupal survival was higher at higher humidities independent of temperature. Survival of X. conformis pupae was lower than that of X. ramesis pupae when the relative humidity was low. Humidity change on later stages (from larva to cocoon) decreased X. conformis pupal survival and had no effect on X. ramesis pupal survival. The sex ratio of emerged adults was not affected by either temperature or humidity in both species. Changes in humidity between egg and larval emvironments significantly decreased the percentage of females in X. conformis emergence at 28 degrees C.
... The dishes were then assigned to a group with 1 g of food, referred as high food treatment and food ad libitum, or to a group with 0.1 g of food referred to as low food. The food was a mixture of dry yeast, dry beef blood, and pulverized dry dog chow in the respective weight proportions 8%, 12% and 80% (Silverman and Rust 1983). Each treatment had 20 replicates. ...
... It also suggests that some nests offer better conditions both for the developmental stages during the reproductive period and for the survival of preemerged imagos overwintering inside the cocoons. Humidity level is known to affect both the development of eggs and larvae (Baccot 1914, Rothschild and Clay 1952, Heeb et al. 2000, and the survival of overwintering adults (Humphries 1967a, Silverman andRust 1983). Variation in humidity within the nests depends on abiotic and biotic factors inside nest boxes (Heeb et al. 2000), and on properties of the microhabitat surrounding nest boxes. ...
... Temperature and relative humidity are factors that influence different developmental flea instars (Beck and Pfister 2004). Extreme temperatures (+35° +38°C) in combination with a relative humidity ≤ 33% profoundly reduce flea population survival (Silvermann et al. 1981, Silvermann andRust 1983). ...
... At 27°C and 80% relative humidity, fleas begin to emerge approximately 5 days after pupation, and they reach peak emergence in 8 to 9 days. The pupa can remain dormant in the cocoon for several weeks, seldom this extends up to 1 year, until a suitable host arrives (quiescence) (Silvermann and Rust 1983). The pupa instar can extend the lifespan of the flea and is troublesome from a control standpoint. ...
Article
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Ectoparasitic insects play a major role in veterinary medicine. Fleas infest man and animals and are the most frequent external parasites of companion animals worldwide. Some species are known to be vectors of zoonotic pathogens. Dogs and cats may play an important role either as reservoir of some of the pathogens or as transport vehicles for infected eas between their natural reservoirs and human beings, thus playing a crucial step in the transmission cycle of ea-borne diseases. This article reviews relevant literature on morphology, classi cation, host speci city, geographical distribution, and seasonality of eas infesting dogs and cats in order to improve their timely identi cation, prevention, and control.
... The dishes were then assigned to a group with 1 g of food, referred as high food treatment and food ad libitum, or to a group with 0.1 g of food referred to as low food. The food was a mixture of dry yeast, dry beef blood, and pulverized dry dog chow in the respective weight proportions 8%, 12% and 80% (Silverman and Rust 1983). Each treatment had 20 replicates. ...
... It also suggests that some nests offer better conditions both for the developmental stages during the reproductive period and for the survival of preemerged imagos overwintering inside the cocoons. Humidity level is known to affect both the development of eggs and larvae (Baccot 1914, Rothschild and Clay 1952, Heeb et al. 2000, and the survival of overwintering adults (Humphries 1967a, Silverman andRust 1983). Variation in humidity within the nests depends on abiotic and biotic factors inside nest boxes (Heeb et al. 2000), and on properties of the microhabitat surrounding nest boxes. ...
Article
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Dispersal has profound effects on parasite populations. Understanding the dispersal behavior of parasites is fundamental to our appreciation of their virulence, epidemiology, and host specificity. Very few host-parasite systems, however, allow for studying how parasites optimize their transmission rates. Here, we investigated the dispersal behavior of a common ectoparasite of European passerine birds, the flea Ceratophyllus gallinae. This flea primarily infests hole-nesting species and breeds during its host's breeding season. Once the host leaves the nest, flea larvae build cocoons, pupate, and remain dormant before initiating their host search. There is considerable variation in the time at which they hatch and disperse from the nest boxes. Some offspring disperse before the hosts choose their nest sites at the beginning of the next breeding period, while others wait until after that stage to disperse. By experimentally manipulating the density of fleas in the nests of their breeding hosts we were able to investigate density-dependent processes that would later affect the dispersal behavior of flea offspring. We found that the density of offspring in the nests was negatively correlated with the proportion of early-dispersing individuals and negatively affected the phenotypic quality of dispersers. Flea offspring of poor phenotypic quality in terms of body size dispersed earlier and had lower potential fecundity than bigger individuals. In a laboratory experiment, we found that the intensity of larval competition strongly affected offspring development, body size at maturity, and overwintering capacity. Thus, in order to maximize their chance of transmission, C. gallinae individuals adjust their dispersal behavior according to their phenotypic quality. In this species, dispersal in time may be explained by the carryover effects of variation in the amount of competition experienced at the larval stage.
... Consequently, ¯ea preferences to these factors are poorly known. Air temperature has been reported to affect the developmental time and emergence of the rat ¯ea, Xenopsylla cheopis Rothschild, 1903, and the cat ¯ea, Ctenocephalides felis Bouche, 1835 (Margalit & Shulov, 1972; Silverman & Rust, 1983; Metzger & Rust, 1997). In the cat ¯ea, eggs hatched in 48 h and larvae spoon cocoons in less than 10 days at 26.7°C, whereas at 15.5°C these periods were extended to 6 and more than 26 days, respectively (Silverman et al., 1981). ...
... Other studies reported no RH effect on the preimaginal development (Parajulee et al., 1995; Oussou et al., 2000). Nevertheless, RH has a profound in¯uence upon preimaginal ¯ea survival (Bruce, 1948; Bahmanyar & Cavanaugh, 1976; Silverman et al., 1981; Silverman & Rust, 1983). We have investigated the effect of the between-habitat distribution of host species on species richness and abundance of ectoparasites using rodent ¯ea assemblages in the Ramon erosion cirque, Negev Highlands, Israel (Krasnov et al., 1997Krasnov et al., , 1998). ...
Article
The rate of development of immature fleas, Xenopsylla conformis Wagner and Xenopsylla ramesis Rothschild (Siphonaptera: Xenopsyllidae) was studied in the laboratory at 25 degrees C and 28 degrees C with 40, 55, 75 and 92% relative humidity (RH). These fleas are separately associated with the host jird Meriones crassus Sundevall in different microhabitats of the Ramon erosion cirque, Negev Highlands, Israel. This study of basic climatic factors in relation to flea bionomics provides the basis for ecological investigations to interpret reasons for paratopic local distributions of these two species of congeneric fleas on the same host. Both air temperature and RH were positively correlated with duration of egg and larval stages in both species. Change of humidity between egg and larval environments did not affect duration of larval development at any temperature. At each temperature and RH, the eggs and larvae of X. ramesis did not differ between males and females in the duration of their development, whereas female eggs and larvae of X. conformis usually developed significantly faster than those of males. For both species, male pupae developed slower than female pupae at the same air temperature and RH. Air temperature, but not RH, affected the duration of pupal development. At each humidity, duration of the pupal stage was significantly longer at 25 degrees C than at 28 degrees C: 15.3+/-1.7 vs. 11.7+/-1.2 days in X. conformis; 14.1+/-2.0 vs. 11.5+/-1.7 days in X. ramesis, with a significantly shorter pupal period of the latter species at 25 degrees C. These limited interspecific bionomic contrasts in relation to basic climatic factors appear insufficient to explain the differential habitat distributions of X. conformis and X. ramesis.
... felis) likely plays an important role in the transmission of R. felis to humans, acting both as a vector and reservoir (Barrs et al., 2010;Hirunkanokpun et al., 2011;Legendre and Macaluso, 2017). The focus in Australia has been on fleas from coastal cities, presumably due to the importance of optimal temperatures and humidity for flea development in these geographical areas (Silverman and Rust, 1983;Metzger and Rust, 1997). Rickettsia felis is able to successfully maintain its population through both horizontal (Hirunkanokpun et al., 2011;Brown et al., 2015) and vertical transmission (Wedincamp and Foil, 2002) which might explain why densely populated areas in Australia have the highest incidence of human R. felis infection cases recorded (Teoh et al., 2016;Hii et al., 2017). ...
Article
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The cat flea (Ctenocephalides felis) is the most common flea species parasitising both domestic cats and dogs globally. Fleas are known vectors of zoonotic pathogens such as vector-borne Rickettsia spp. and Bartonella spp. and could theoretically transmit Coxiella burnetii, the causative agent of Q fever. A total of 107 fleas were collected from 21 cats and 14 dogs in veterinary clinics, a feline rescue organisation and a grooming salon in New South Wales, Australia, to undergo PCR detection of Bartonella spp., Rickettsia spp. and C. burnetii DNA. Morphological identification confirmed that the cat flea (C. felis) is the most common flea in New South Wales, Australia, with only a single stick fast flea, Echidnophaga gallinacea recorded. The examined fleas (n = 35) at the cox1 locus revealed five closely related C. felis haplotypes (inter-haplotype distance < 0.5%). Multiplex TaqMan qPCR targeting the gltA (Rickettsia spp.) and ssrA (Bartonella spp.) genes was positive in 22.9% (95% CI: 11.8–39.3%) and 11.4% (95% CI: 3.9–26.6%) of samples, respectively. None of the DNA isolated from fleas was positive on TaqMan qPCRs targeting the C. burnetii IS1111, Com1 and htpAB genes. Co-infection of C. felis with B. henselae and B. clarridgeiae was demonstrated using gltA and ssrA Illumina next-generation amplicon sequencing. These findings reinforce the importance of flea control on domestic dogs and cats to effectively control the transmission of R. felis and Bartonella spp. The flea, however, is unlikely to be a vector of C. burnetii between companion animals and humans.
... A comparison of the different B. henselae temperature and pH conditions mimicking both vector and host to determine the condition(s) that may enhance/eliminate the formation of the stem loop in our laboratory was not productive. Temperature ranges between 27 • C (arthropod vector) and 37 • C (mammalian host), and pH values between 6.6 and 7.2 to coincide with vector and human blood pH, respectively, did not show any significant differences in trp transcription or biofilm formation [16,[101][102][103][104][105][106]. ...
Article
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Bartonella henselae (B. henselae) is a gram-negative bacterium that causes cat scratch disease, bacteremia, and endocarditis, as well as other clinical presentations. B. henselae has been shown to form a biofilm in vitro that likely plays a role in the establishment and persistence of the bacterium in the host. Biofilms are also known to form in the cat flea vector; hence, the ability of this bacterium to form a biofilm has broad biological significance. The release of B. henselae from a biofilm niche appears to be important in disease persistence and relapse in the vertebrate host but also in transmission by the cat flea vector. It has been shown that the BadA adhesin of B. henselae is critical for adherence and biofilm formation. Thus, the upregulation of badA is important in initiating biofilm formation, and down-regulation is important in the release of the bacterium from the biofilm. We summarize the current knowledge of biofilm formation in Bartonella species and the role of BadA in biofilm formation. We discuss the evidence that defines possible mechanisms for the regulation of the genes required for biofilm formation. We further describe the regulation of those genes in the conditions that mimic both the arthropod vector and the mammalian host for B. henselae. The treatment for persistent B. henselae infection remains a challenge; hence, a better understanding of the mechanisms by which this bacterium persists in its host is critical to inform future efforts to develop drugs to treat such infections.
... At 24 ∘ C and 75% relative humidity, the duration of the three larval instars is about 1 week, but at 13 ∘ C and 75% relative humidity larval development takes about 5 weeks, although the larval cycle can take up to 200 days under more unfavourable conditions. Larvae will only survive at temperatures between about 13 and 35 ∘ C and they are extremely susceptible to desiccation; mortality is high below 50% relative humidity and outdoors flea larvae cannot develop in arid areas exposed to the hot sun (Silverman & Rust, 1983). As a result, in the northern hemisphere, changing abundance generally shows a seasonal pattern with numbers increasing around late spring and early autumn when environmental conditions are favourable for larval development (Rinaldi et al., 2007). ...
Article
The spatial pattern of flea (Siphonaptera: Pulicidae) infestation risk in cats and dogs across Great Britain is quantified, using data collected from a national survey undertaken in 2018, with particular attention given to the association between insecticidal treatment and infestation risk. Flea infestation risk declined significantly from south to north. None of the factors: pet breed, sex, neutered status or whether the pet had been abroad, showed any relationship with the underlying geographic distribution, which is most likely to be associated with climatic factors. However, overall, only 23.6% of the cats and 35% of the dogs inspected had been treated with identifiable flea products that were still ‘in date’ at the point of inspection. The percentage of owners treating their pet broadly followed infestation risk. The insecticide fipronil is a common active in a wide range of flea treatments and was the most frequently applied insecticide class, particularly in cats. However, 62% of cats and 45% of dogs that had been treated with a fipronil‐based product that was ‘in date’ at the point of inspection still had fleas. Persistent flea infestation is likely to be due to a range of factors, including compliance and application failure, but the data provide strong inferential evidence for a lack of efficacy of fipronil‐based products. Given the ubiquity of flea infestation, this finding and the relatively low‐level of treatment compliance, highlight a clear need for greater owner education about the importance of flea management and a better understanding of the efficacy of different products.
... The pupal stage is highly resistant to desiccation, but temperatures <8°C and >35°C, are lethal. Larvae die if levels of soil moisture are >20%, or <1% (Silverman and Rust 1983) Effects of climate change From these data, it is apparent that New Zealand, is likely to remain a very suitable habitat for both cat and dog fleas and may become more so under global warming, given that the temperature range tolerated by both species of fleas is unlikely to change sufficiently to affect survival and populations. It could be that higher and more frequent precipitation could raise ambient humidity to unsuitable levels in some months, a scenario that may be seen in western areas of New Zealand under marked climate change. ...
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Climate change, in the form of global warming, is a current concern, and because they are influenced by weather, it is possible to predict (albeit with some uncertainty) that farming systems, livestock parasites and their hosts will change in some broadly descriptive fashion as climate changes. This review examines the on- and off-host responses to potential changes in temperature and humidity of a representative selection of arthropod ectoparasites (sheep biting louse, sheep blowflies, cattle tick, chorioptic mange mite and cat and dog fleas) that occur in New Zealand and in many other countries , and how these environmental factors can be perturbed by host manipulation. The bioclimatic preferences of the parasites are examined in relation to future broad climate parameters and how parasite life cycles, seasonality and population dynamics may be influenced. Likely adaptations of farming systems to meet climate change imperatives are briefly discussed. Collectively it is estimated that regions of New Zealand faced with warmer, wetter conditions under climate change may see an increase in flystrike and cattle tick prevalence, and perhaps an increase in the biting louse, but fewer chorioptic mange and flea infestations. In contrast, drier, warmer regions will possibly experience fewer of all ectoparasites with the exception of flea infestations. Economic effects of increases in ectoparasite prevalence, using approximate dipping costs as a model are examined, and risks posed to New Zealand by some exotic arthropod parasites with the potential to invade under climate change, are briefly outlined.
... Evidence suggests that humans began migrating out of Africa as early as 120,000 years ago but did not reach the Americas until 15,000 years ago, possibly explaining the more recently evolved community of cat fleas in the Americas, characterised by low genetic diversity (Goebel et al., 2008;Stringer, 2011Stringer, , 2016Groucutt et al., 2015). Similar to all ectoparasites with 'off-host' life stages, Ctenocephalides flea growth and reproduction is highly dependent upon environmental conditions and climatic factors such as air temperature and precipitation or humidity (Silverman et al., 1981;Dryden and Rust, 1994;Silverman and Rust, 1983;Dryden and Rust, 1994). The results of our analysis showed that, as a species, C. felis demonstrates high levels of ecological plasticity with a broad spectrum of suitable bioclimatic regions highlighted across multiple climatic zones. ...
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The cat flea (Ctenocephalides felis) is the most common parasite of domestic cats and dogs worldwide. Due to the morphological ambiguity of C. felis and a lack of — particularly largescale — phylogenetic data, we do not know whether global C. felis populations are morphologically and genetically conserved, or whether human-mediated migration of domestic cats and dogs has resulted in homogenous global populations. To determine the ancestral origin of the species and to understand the level of global pervasion of the cat flea and related taxa, our study aimed to document the distribution and phylogenetic relationships of Ctenocephalides fleas found on cats and dogs worldwide. We investigated the potential drivers behind the establishment of regional cat flea populations using a global collection of fleas from cats and dogs across six continents. We morphologically and molecularly evaluated six out of the 14 known taxa comprising genus Ctenocephalides, including the four original C. felis subspecies (Ctenocephalides felis felis, Ctenocephalides felis strongylus, Ctenocephalides felis orientis and Ctenocephalides felis damarensis), the cosmopolitan species Ctenocephalides canis and the African species Ctenocephalides connatus. We confirm the ubiquity of the cat flea, representing 85% of all fleas collected (4357/5123). Using a multigene approach combining two mitochondrial (cox1 and cox2) and two nuclear (Histone H3 and EF-1α) gene markers, as well as a cox1 survey of 516 fleas across 56 countries, we demonstrate out-of-Africa origins for the genus Ctenocephalides and high levels of genetic diversity within C. felis. We define four bioclimatically limited C. felis clusters (Temperate, Tropical I, Tropical II and African) using maximum entropy modelling. This study defines the global distribution, African origin and phylogenetic relationships of global Ctenocephalides fleas, whilst resolving the taxonomy of the C. felis subspecies and related taxa. We show that humans have inadvertently precipitated the expansion of C. felis throughout the world, promoting diverse population structure and bioclimatic plasticity. By demonstrating the link between the global cat flea communities and their affinity for specific bioclimatic niches, we reveal the drivers behind the establishment and success of the cat flea as a global parasite.
... Amerika Birleşik Devletlerinde yapılan bir araştırmada 24 veteriner kliniğine köpeklerini getiren toplam 478 kişiden %73'ü (350 kişi) köpeklerini 12 ay boyunca pire ve kenelere karşı korumalarının gerektiğini düşünüyorken, %17'lik bir grup (49 kişi) 6 ay veya daha az bir sürenin koruma için yeterli olduğunu düşünmektedir (11). Uygun olmayan koşullarda uzun süre pupa (kokon) evresinde kalabilen Ct. felis türü pirelerin ortam sıcaklığı 8°C'nin üzerine yükseldiğinde ortaya çıkan yetişkinlerinin yaklaşık yarısı 20 gün boyunca hayatta kalabilirler (12). Yaban hayvanlarının soğuğa karşı korunaklı inlerinde veya yuvalarında pireler uzun süre hayatta kalabilirler (7). ...
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Objective: Many pet owners are taking precautions to protect their cats and dogs from ectoparasites only during the spring and summer months. However, some studies have shown that fleas can also be found as parasites on pets during winter. In this research, we investigated the species composition of fleas infesting cats and dogs that were brought to a veterinary clinic in Muratpasa, Antalya during the 3-months survey period. Methods: In total, 50 domestic animals were examined between December 1, 2017 and February 28, 2018. Species of fleas were identified after being collected from pets. Results: Total 152 fleas, belonging to 2 different species, were recovered from pets. Of the domestic animals, 46% were cats (23) and 54% were dogs (27). Twenty two cats were infested with only Ctenocephalides felis. Nineteen dogs were infested with only Ct. felis, 5 dogs infested with only Ct. canis, and 3 dogs infested with both Ct. felis and Ct. canis. Conclusion: This research showed that infestation with fleas should be monitored and controlled in both cats and dogs during winter months as well.
... Aquatic, temporary-lentic or intermittent-lotic water bodies, deserts Arlian and Staiger, 1979;Pallarés et al., 2016 Siphonaptera Spilopsyllus cuniculi Egg, larva, pupa, adult External parasite of rabbits Cooke and Skewes, 1988 Ctenocephalides felis Egg, larva, pupa, adult External parasite of cats Silverman and Rust, 1983 contrast, SOD serves as the major antioxidant in B. antarctica (Benoit and Lopez-Martinez, 2012). Recently, the role of unconventional antioxidant molecules such as trehalose, proline, polyamines and polyoils has gained attention (Goyal et al., 2004;Schill et al., 2009;Benoit and Lopez-Martinez, 2012). ...
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The year 2002 marked the tercentenary of Antonie van Leeuwenhoek’s discovery of desiccation tolerance in animals. This remarkable phenomenon to sustain ‘life’ in the absence of water can be revived upon return of hydrating conditions. Today, coping with climate change-related factors, especially temperature-humidity imbalance, is a global challenge. Under such adverse circumstances, desiccation tolerance remains a prime mechanism of several plants and a few animals to escape the hostile consequences of fluctuating hydroperiodicity patterns in their habitats. Among small animals, insects have demonstrated impressive resilience to dehydration and thrive under physiological water deficits without compromising on revival and survival upon rehydration. The focus of this review is to compile research insights on insect desiccation tolerance, gathered over the past several decades from numerous laboratories worldwide working on different insect groups. We provide a comparative overview of species-specific behavioral changes, adjustments in physiological biochemistry and cellular and molecular mechanisms as few of the noteworthy desiccation-responsive survival kits in insects. Finally, we highlight the role of insects as potential mechanistic models in tracking global warming which will form the basis for translational research to mitigate periods of climatic uncertainty predicted for the future.
... Brisbane's climate is more moderate than northern Florida and cat fleas were reported year round in Brisbane. In protected microhabitats in southern California, cat fleas developed when temperatures exceeded 4°C (Silverman and Rust 1983). Cooperators in Australia relied heavily on the veterinary school's clinic that neuters pets to obtain flea isolates and this program is typically at its peak from August to October. ...
Article
An international team of scientists and veterinarians was assembled in 1999 to develop a monitoring program to determine the susceptibility of cat fleas, Ctenocephalides felis felis (Bouché) (Siphonaptera: Pulicidae), to imidacloprid. Cat flea eggs were collected, shipped to laboratories, and tested for their susceptibility to imidacloprid. Over 3,000 C. felis populations were collected from 2002 to 2017 from 10 different countries. Of these, 66.3% were collected from cats and 33.7% from dogs. C. f. felis populations (n = 2,200) were bioassayed by exposing cat flea eggs and the emerging larvae to a Diagnostic Dose (DD) of 3 ppm imidacloprid in larval rearing medium. Flea eggs hatched and developed in the untreated controls in 1,837 of the isolates (83.5%) bioassayed. Flea isolates (n = 61) that had ≥5% survival at the DD of 3 ppm were retested with a second DD of 3 ppm. None of them had ≥5% survival to the second dose of 3 ppm. Of the 1,837 valid C. felis isolates tested, there has been no evidence of a decreased susceptibility to imidacloprid over the past 17 yr. The methods outlined in this article should provide an acceptable protocol for testing many of the new active ingredients that have been registered for cat flea control.
... Several studies have focused on assessing the critical limits of environmental factors that constraint organisms and limit their distribution (Castañeda et al., 2004;Klok et al., 2004;Silverman and Rust, 1983;Stevens et al., 2010). Sub-optimal conditions are nonetheless the most usual circumstance in nature and might also affect several fitness-enhancing activities (Bednarska et al., 2010). ...
... Steinernema carpocapsae is commercially available, is marketed as effective against fleas, and could be considered if its use was practical and proven efficacious. This nematode must be applied to soil that is moist (≥20% moisture), among other things, which limits its practicality and efficacy, particularly since the soil moisture content that best suits cat flea larvae development is 1 -10% [63,65,67]. Vaccination of dogs and cats against fleas or ticks may be possible in the future, but is not a current option [5,[68][69][70]. ...
Article
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This review defines insecticide/acaricide resistance and describes the history, evolution, types, mechanisms, and detection of resistance as it applies to chemicals currently used against fleas and ticks of dogs and cats and summarizes resistance reported to date. We introduce the concept of refugia as it applies to flea and tick resistance and discuss strategies to minimize the impact and inevitable onset of resistance to newer classes of insecticides. Our purpose is to provide the veterinary practitioner with information needed to investigate suspected lack of efficacy, respond to lack of efficacy complaints from their clients, and evaluate the relative importance of resistance as they strive to relieve their patients and satisfy their clients when faced with flea and tick infestations that are difficult to resolve. We conclude that causality of suspected lack of insecticide/acaricide efficacy is most likely treatment deficiency, not resistance.
... Soil moisture itself impacts flea survival: even at low ambient relative humidity (12%), increasing soil moisture of sand or sandy clay from zero to 1% increased larval survival from zero to 100%. On silty clay soils, larval survival increased above 5% soil moisture because clay binds water, making it unavailable at low levels (Silverman and Rust 1983). The dry conditions and clay soils normally found on the shortgrass steppe clearly have an impact, but the relationship between 1.5 mPa soil moisture capacity and plague transmission and persistence requires further exploration. ...
Article
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Outbreaks of plague in wildlife are sporadic and spatially dispersed, and they depend on coincidence of susceptible hosts, flea vectors, the plague bacterium (Yersinia pestis), and environmental factors that support pathogen transmission. We fit spatial models of plague outbreaks to a long-term data set (1981–2005) of towns of black-tailed prairie dogs (Cynomys ludovicianus) on the shortgrass steppe of northeastern Colorado. We investigated the effects of spatial distribution (town area and connectivity to other prairie dog towns), climate (spring and summer precipitation and temperature), and soil moisture-holding capacity. In logistic regression models, plague epizootics were predicted by connectivity to other towns experiencing plague during periods with relatively low temperatures, in soils with high moisture-holding capacity. After accounting for connectivity between prairie dog towns and current-year climatic conditions, little additional spatial or temporal autocorrelation was detected. Spatial logit association models provided evidence for localized epizootic hotspots and that greater summer rainfall predicted plague events. Plague outbreaks were not predicted by precipitation in the previous year. As such, no evidence was found to support an indirect cascade model of plague outbreaks for black-tailed prairie dogs on the shortgrass steppe in Colorado. Instead, the models suggest that plague occurrence depends upon direct climatic effects on flea vectors and the plague pathogen.
... Beyond this value, survival of immature stages decreases, especially in the presence of low humidity [52]. Temperatures >35°C and <3°C, in combination with a relative humidity <33%, may impair flea development [59][60][61]. Accordingly, the vast majority of past plague cases have been described in those regions where average temperatures are >13°C, with outbreaks occurring when temperature ranges from 24°C to 27°C and a decrease of epidemic activities at higher values [62][63][64]. Additionally, rainfall favours vegetative production, increase of small-mammal populations, rat flea-infestation rates, along with soil moisture, which promotes flea survival rates [65,66]. ...
Article
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Modifications in climatic conditions, movements of hosts and goods, changes in animal phenology and human behaviour and increase of wildlife, are presently concurring in the geographic spread of vectors and cardio-respiratory nematodes, e.g. Dirofilaria immitis, Angiostrongylus vasorum, Aelurostrongylus abstrusus and Capillaria aerophila. All these factors may also influence dispersion and clinical significance of fleas, thus posing relevant challenges in those regions where other parasites are emerging at the same time. Ctenocephalides felis, Ctenocephalides canis and Pulex irritans cause discomfort, nuisance, allergic reactions, anaemia, and may transmit several pathogens, some of them are of importance for public health. The present article reviews the importance of fleas in small animal practice and their sanitary relevance for dogs, cats and humans, and discusses current control methods in the present era of emerging extra-intestinal nematodes, towards a possible changing perspective for controlling key parasites affecting companion animals.
... The different climatic conditions in these areas, particularly with regard to temperature and humidity, may interfere with the biological cycles of the fleas in the two regions. Temperatures above 35 °C and below 3 °C and relative humidity less than 33% reduce the population of fleas in the environment (SILVERMANN et al., 1981;RUST, 1983). During the rainy season in Nanuque, the temperature is high (31 to 34 °C) and may not benefit the fleas, which are more prevalent in the dry season. ...
Article
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The present study examined occurrences of ectoparasites and identified them on dogs in rural regions in Brazil, and assessed the influence of climate on these parasites. Ectoparasites were randomly collected from 194 dogs living on farms located in Lavras (n = 92) and Nanuque (n = 102) during the dry season. During the subsequent rainy season, the same dogs in Lavras (n = 71) and Nanuque (n = 66) were resampled. During the experiment, fleas, ticks, lice and fly larvae were collected. The flea species Ctenocephalides felis was the most common ectoparasite collected from these dogs. The main tick species that infested the dogs in rural areas of Nanuque and Lavras was Amblyomma cajennense. In Lavras, the dogs had high levels of flea infestation (80.4 and 88.7% in the dry and rainy seasons, respectively) and low levels of tick infestation (19.6 and 28.2% in the dry and rainy seasons, respectively), without any significant differences in infestation rates between the seasons. In Nanuque, moderate levels of flea infestation (68.6 and 43.9% in the dry and rainy seasons, respectively) and A. cajennense (65.7 and 47.0% in the dry and rainy seasons, respectively) were observed, with significantly lower prevalence in the rainy season (p < 0.05). The presence of ectoparasites was evident at both times of the year, but the different temperatures may have influenced the occurrences of parasites in Lavras and Nanuque.
... 35 C) the air must be moist (75-92% RH) to avoid desiccation of cat flea eggs, yet failure to hatch may be due to an accumulation of heat within the egg [190]. Under experimental conditions, cat flea larvae and pupae did not survive temperatures >35 C for >40 h/month, when the relative humidity was constant at 75% [191]. Furthermore, very high larval mortality was reported in sunexposed areas (100%) and inside structures that trapped heat, such as kennels (100%) [192], suggesting that fleas are not well adapted to very hot tropical regions. ...
... At 27 C (80.6 F) and 80% relative humidity, fleas begin to emerge approximately 5 days after pupation, and they reach peak emergence in 8 to 9 days. 10,11 Once the pupa has fully developed, the pre-emerged adult flea within the cocoon can be stimulated to emerge from the cocoon by physical pressure, carbon dioxide, and heat. 12 If the pre-emerged adult does not receive an emergence stimulus, it may remain quiescent in the cocoon for several weeks or months until a suitable host arrives. ...
Article
Flea and tick infestations are common and elimination can be expensive and time consuming. Many advances in control of fleas can be directly linked to improved knowledge of the intricacies of flea host associations, reproduction, and survival in the premises. Understanding tick biology and ecology is far more difficult than with fleas, because North America can have up to 9 different tick species infesting cats and dogs compared to 1 primary flea species. Effective tick control is more difficult to achieve than effective flea control, because of the abundance of potential alternative hosts in the tick life cycle. Many effective host-targeted tick control agents exist, several of which also possess activity against adult or immature fleas and other parasites.
... These results are consistent with other studies [12][13][14] that have examined the role of temperature and precipitation variables on plague outbreaks in human and animal populations. In addition to having a positive effect on rodent population dynamics, certain soil moisture, humidity and temperature variables may influence flea ecology and the transmission of the plague pathogen [53]. Specifically, while warmer temperatures may in general stimulate plague activity, temperatures above 35 degrees Celsius are associated with a negative effect on flea fecundity, survival, and behavior [13,18,54]. ...
Article
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Plague, caused by the bacterium Yersinia pestis, is a public and wildlife health concern in California and the western United States. This study explores the spatial characteristics of positive plague samples in California and tests Maxent, a machine-learning method that can be used to develop niche-based models from presence-only data, for mapping the potential distribution of plague foci. Maxent models were constructed using geocoded seroprevalence data from surveillance of California ground squirrels (Spermophilus beecheyi) as case points and Worldclim bioclimatic data as predictor variables, and compared and validated using area under the receiver operating curve (AUC) statistics. Additionally, model results were compared to locations of positive and negative coyote (Canis latrans) samples, in order to determine the correlation between Maxent model predictions and areas of plague risk as determined via wild carnivore surveillance. Models of plague activity in California ground squirrels, based on recent climate conditions, accurately identified case locations (AUC of 0.913 to 0.948) and were significantly correlated with coyote samples. The final models were used to identify potential plague risk areas based on an ensemble of six future climate scenarios. These models suggest that by 2050, climate conditions may reduce plague risk in the southern parts of California and increase risk along the northern coast and Sierras. Because different modeling approaches can yield substantially different results, care should be taken when interpreting future model predictions. Nonetheless, niche modeling can be a useful tool for exploring and mapping the potential response of plague activity to climate change. The final models in this study were used to identify potential plague risk areas based on an ensemble of six future climate scenarios, which can help public managers decide where to allocate surveillance resources. In addition, Maxent model results were significantly correlated with coyote samples, indicating that carnivore surveillance programs will continue to be important for tracking the response of plague to future climate conditions.
... The determinants of flea abundance in a particular region or on a particular host species include more than the suitability of the host for the flea. Because fleas spend a significant portion of their life off the host, i.e. in its nest or burrow, physical factors such as temperature and humidity also play major roles in flea reproduction and survival (see Silverman and Rust, 1983;Metzger and Rust, 1997;Krasnov et al., 2001a,b). There is substantial visiting and sometimes even sharing of burrows between different mammal species (Kucheruk, 1983), and local climatic conditions will likely be similar for all host burrows present in one region. ...
Article
The strength of interspecific interactions varies over geographical scales, and can influence patterns of resource specialisation. Even with gene flow preventing local adaptation of a consumer to particular resources, we might expect that across its entire range, the consumer would show some specialisation for the resource types most likely to be encountered across the localities where it occurs. We tested the hypothesis that generalist fleas are more successful at exploiting small mammalian host species with which they co-occur frequently across their geographical range than host species that, though suitable, are encountered less frequently. This hypothesis was tested with data on 121 flea species compiled from field surveys across 35 regions of the Palaearctic. Using abundance (mean number of individual fleas per individual host) as a measure of flea success on a particular host species, positive correlations between flea abundance and the frequency of co-occurrence of a flea with each of its hosts amongst all regions surveyed were found in all but two of the flea species investigated, with one-fifth of these being significant. If overlap in geographical range between flea and host is used as a measure of frequency of encounters instead of the actual proportion of regions where they both occur, similar patterns are observed, though they are much weaker. In a comparative analysis across all flea species, there were significant relationships between the average abundance of fleas and average values of both measures of frequency of encounters (proportion of sites where they co-occur and range overlap), even when correcting for potential phylogenetic influences. The results suggest that for any given flea species, host species more commonly encountered throughout the spatial range of the flea are generally those on which the flea does best. Interaction frequency may be a key determinant of specialisation and abundance in host-parasite systems.
Article
The cat flea (Ctenocephalides felis) is a competent vector of numerous bacterial pathogens in the genera Bartonella and Rickettsia. In the United States, free-roaming domestic cats (Felis catus) increase the risk of exposure to C. felis for humans and their companion animals. In collaboration with a trap-neuter-return program, we collected fleas from 283 feral/stray cats in southeastern Georgia between May and July of 2020. A total of 3643 flea specimens were collected, and C. felis was the only flea species recovered from all cats sampled. The mean number of fleas per cat host was highest in the month of June when compared to May and July, and higher in juvenile cats (< 1 year) than the adults (≥ 1 year). Real-time PCR assays were used to test a subset of the collected fleas (n = 468) for the presence of Bartonella spp. and Rickettsia spp. DNA. Among those flea pools tested, 35.2% were positive for genus-specific citrate synthase gene of Bartonella, 16.5% were positive for the genus-specific 17-kDa protein antigen gene of Rickettsia, and none were positive for the species-specific outer membrane protein B gene of Rickettsia typhi. The identification of potential flea-borne pathogens was more frequent from the subset of C. felis collected in May, and female cats had more Bartonella-positive fleas and less Rickettsia-positive fleas than male cats. Overall, the present study provides valuable insights into the frequency of C. felis from outdoor community cats in southeastern Georgia, and highlights the possible risk for human exposure to potential flea-borne pathogens.
Article
While the prevalence of some UK parasites such as Toxocara spp. remains fairly constant despite fluctuations in climate, some other parasites are heavily dependent on mild, humid conditions to feed and reproduce. Recent mild winters and wet summers in the UK have benefitted three parasites in particular. Angiostrongylus vasorum has continued to spread across the UK with increased distribution and numbers of infected foxes, numbers of flea infestations appear to have increased in domestic cats and dogs, and Ixodes spp. tick numbers have increased with a longer seasonal period of activity. Veterinary professionals need to be aware of these changes in distribution and increased risk of disease transmission to domestic pets. This article discusses these changes and how they should inform advice given to clients.
Article
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Fleas are the most common and important external parasites worldwide and also serves as vectors of various pathogens for humans and animals. The study aimed to determine the prevalence of Pulex irritants in sheep herds and residential areas of villages in Kurdsitan Province, Iran. A total of 2,900 sheep were randomly selected from 48 flocks and 630 residential areas of 18 villages from November 2011 to October 2012. The collected fleas were identified by key fleas. Results revealed that 259 (8.93%) sheep from 31 flocks (65.51%) and 31 (4.92%) residential areas were infested with P. irritants. Of 1323 P. irritants, 503/1323 (38.02%) and 820/1323 (61.98%) were male and female, respectively. Of these, 950 (72%) were from animals and 373 (28%) were from residential areas. The highest infection rate was found in age group less than one year (30.93%, 29/92). The body distribution of all collected flea was found to be from back part of the body (100%). Seasonal distribution of P. irritants in examined animals had significant difference. Geographical distribution of P. irritants indicated that the highest infection rate was found in Marab region (6.03%). The highest flea infestation was also found in summer (41.8%) with a total number of 450 fleas out of 1323 (34.01%). From the results of this study, it was concluded that P. irritants was a prevalent flea in sheep and residential areas in the region and may serve as an important vector for pathogenic agents.
Article
The relationship between primates and lice is discussed. Lice are ectoparasites that live on the body surface of mammals and, in contrast to ticks and fleas, do not leave the host during their life cycle. Host mammals may experience adverse effects from lice, such as anemia and skin irritation. Moreover, lice are vectors of infectious diseases; for example, human lice (Pediculus humanus) transmit the epidemic typhus pathogen between humans (Homo sapiens). DDT virtually eliminated human lice in several countries after World War II. Early Japanese primatologists who began research during this period had little interest in the relationship between primates and lice. Primates groom each other to remove lice, ticks, and small objects. Prosimians use their lower incisors to groom, similar to rodents and African antelopes, whereas anthropoids, which have a retinal fovea with high visual acuity and functional fingers that allow them to find and pick small ectoparasites from the body surface, groom using their hands and mouth. Japanese monkeys (Macaca fuscata) and lice (Pedicinus obtusus, P. eurygaster) have an entwined host-parasite and predator-prey relationship. Lice lay nits on monkeys, who are hosts, in areas where hair growth is dense because the hair conceals nits from the monkeys, who are their predators. Monkeys remove and eat nits according to nit density. Given the high intrinsic rate of natural increase in lice, monkeys need to groom daily. This necessity may explain why monkeys live with grooming partners making social groups. The development of simplified techniques to estimate louse infection in primates will advance the study of socioecological models and lice infection dynamics in primate metapopulations.
Article
Plague is emerging as a threat to humans and wildlife throughout western North America. Sylvatic plague, caused by the bacterium Yersinia pestis, is maintained within a network of mammal species and their fleas. No 'classic' reservoir has been identified; no resistant host species is known to develop sufficient bacteremia to support vector transmission. Epizootics are detected through the observation of mass mortality in conspicuous species like prairie dogs. Prairie dogs have key effects on both the ecological and epidemiological dynamics of prairie communities. The diversity of small mammals is lower in prairie dog colonies, despite higher densities of certain species on colonies relative to other grassland sites. This pattern suggests increased competition or apparent competition in colonies, perhaps through shared use of prairie dog burrows. Graphical models demonstrate how the ratio of interspecific to intraspecific interactions may be altered in colonies, affecting the potential for plague transmission in complex ways.
Conference Paper
Concluding remarks: Fleas are strongly specialized to periodic ectoparasitism on small mammals and demonstrate a variety of life histories and associations with their hosts. This makes fleas a very convenient model for testing hypotheses related to evolutionary ecology of parasitism. Some of these studies will be reviewed in further chapters of this book.
Book
Fleas are one of the most interesting and fascinating taxa of ectoparasites. All species in this relatively small order are obligatory haematophagous (blood-feeding) parasites of higher vertebrates. This 2008 book examines how functional, ecological and evolutionary patterns and processes of host-parasite relationships are realized in this particular system. As such it provides an in-depth case study of a host-parasite system, demonstrating how fleas can be used as a model taxon for testing ecological and evolutionary hypotheses. The book moves from basic descriptive aspects, to functional issues and finally to evolutionary explanations. It extracts several general principles that apply equally well to other host-parasite systems, so it appeals not only to flea biologists but also to 'mainstream' parasitologists and ecologists.
Article
Parasitic, infectious and vector-borne diseases of humans and animals thrive in the typically hot and humid environment of the tropics. Many countries in these regions of the world remain underdeveloped with limited resources at their disposal to effectively combat the tremendous disease burdens borne by their human populations. Research, surveillance and control of veterinary diseases have been given priority only when those diseases have an impact on poverty alleviation or if they pose a significant zoonotic threat to the community. In some societies however, in Asia in particular, economic growth and increasing affluence has resulted in changing attitudes towards companion animal ownership and with this has come increasingly higher expectations and demands on veterinary surgeons for improved knowledge in canine and feline medicine and surgery. Yet despite expanding access to information technology, regionally pertinent information for veterinarians concerning the epidemiology, diagnosis and management of tropical diseases of these companion animals is scarce. The paper aims to redress this imbalance by providing, for the first time, a comprehensive review of the parasitic diseases of cats and dogs in the tropics. The first section discusses diseases and parasites of zoonotic importance; echinococcosis, toxocariasis, ancylostomiasis, the liver and intestinal flukes, gnathostomiasis, toxoplasmosis, leishmaniasis and American trypanosomiasis. In the second section the parasitic diseases of clinical importance for the animals themselves are considered, including babesiosis, dirofilariasis, hepatozoonosis, ectoparasitic diseases, angiostrongylosis and spirocercosis, with information provided on the diagnosis and treatment of these diseases.
Article
The effect of nematode Steinernema carpocapsae on cat flea larvae and pupae in different substrates was studied. Nematode application to potting soil, sand, or gravel substrates containing flea eggs, larvae or pupae reduced adult flea emergence; the effects on sand and gravel were equivalent to and greater than the effects on soil. To determine if the cat flea cocoon provides protection from nematodes, pupae in cocoons of silk, sand and silk, or naked (without cocoons) were placed in close proximity to nematodes. All pupae in cocoons or naked were susceptible to nematode attack. When nematode numbers were increased from one to 25 per cocoon the chance for flea infections also increased.
Article
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Prevalence and seasonal distribution of Ctenocephalides canis (Curtis) and Ctenocephalides felis (Bouché) infestations in urban dogs of the city of Aguascalientes, Mexico, were studied. Between January and December 2007, 863 dogs in the Municipal Canine and Feline Control Center were examined. Overall prevalence of infestation was 12% (95% CI 10-14). Seasonal distribution revealed that prevalences in spring and summer were highest, while autumn and winter had lower prevalences. Two infestation peaks were observed, i.e., in April (17.7%) and July (18.9%). A positive correlation was detected between prevalence and temperature during the winter season (P < 0.05). Prevalence in relation to gender showed that males were more frequently infested, 14% (95% CI 11-17), than females, 9.4% (95% CI 7-13); hair length did not affect differences in prevalence. Six hundred twenty-nine fleas were examined; 62% were C. canis and 38% C. felis . Dogs infested with only C. canis were 48% (95% CI 38-58), while 18% were infested only with C. felis (95% CI 11-27); the remainder, 34% (95% CI 24-44), had mixed infestations.
Article
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We studied the effect of density of larvae on pre-imaginal development in 2 flea species (Xenopsylla conformis and Xenopsylla ramesis) parasitic on 2 desert rodent species (Dipodillus dasyurus, adult body mass 20 g and Meriones crassus, 80 g). We predicted a decrease in duration of development with an increase in density of larvae. In general, in both flea species, duration of larva-to-pupa development decreased with an increasing larval density. In addition, this stage of development was longer in male fleas and in fleas from parents fed on D. dasyurus. The effect of larval density on larval development was manifested mainly when parent fleas fed on D. dasyurus. Duration of pupation decreased with increasing larval density only in offspring of fleas fed on G. dasyurus. In both fleas, pupation was longer in males. The effect of parent host on duration of pupation was found in X. ramesis only (longer if the host was M. crassus). Resistance of newly emerged fleas to starvation depended mainly on parent host species. Young X. conformis survived longer if their parents fed on D. dasyurus, whereas young X. ramesis survived longer if their parents fed on M. crassus. It was also found that (a) an individual flea that spent more time as a larva also spent more time as a pupa and (b) longer larval development resulted in a shorter time that a newly emerged flea was able to survive when starved.
Article
Cat fleas, Ctenocephalides felis, were released onto calves as unusual hosts, and sampled at intervals for histological examination. Egg output from fleas on age-matched male and female calves was monitored. Using indicators of reproductive maturation and regression together with egg output data, the reproductive success and fertility of cat fleas on male and female calves were estimated. Comparisons were made with fleas taken from cats. The mean egg output of fleas on the bull calf was highly significantly different from that on the age-matched female calf: 28.14 +/- 2.96 (SE) eggs/h compared with 16.21 +/- 1.96 (SE) eggs/h. A higher proportion of sampled fleas (83.0%) was reproductively mature on the feline hosts compared with the calves (45.4-62.5%). Blue bodies resulting from oocyte resorption were present in the ovarioles of 10.4-19.0% of fleas sampled from the calves. No blue bodies were present in fleas removed from cats. Eggs laid by fleas on calves were viable and larvae were reared to adulthood. The mean percentage hatching success on the age-matched male and female calves was 46.7% and 51.7%. This represents a reduction in viability of 28-33% compared with eggs laid by fleas on cats. Factors which may account for reduced reproductive maturation of fleas on calves, including protein content of the host's blood, are discussed.
Article
Oocyte development in adult female cat fleas, Ctenocephalides felis (Bouché), was studied by light and electron microscopy to determine the formation and ultrastructural morphology of the eggshell. As oocytes develop, somatic follicle cells from the lining of the ovariole migrate around the oocytes. The follicle cells produce electron-dense granules that form the vitelline membrane around the developing oocyte. Subsequently, electron-lucent granules containing an electron-dense core (precursors of the chorion) are produced from the rough endoplasmic reticulum that appear as dilated and clear linear clefts in the cytoplasm of the follicle cells. Exocytosis and coalescence of the granules around the oocyte as the follicle cells disintegrate give rise to the chorion. The chorion was found to consist of 4 distinct layers. The external surface of the egg shell consists of a particulate layer approximately 760 nm thick, composed of an electron-lucent layer of widely dispersed granules. Embedded in this layer are electron-dense spheres that project above the surface of this granular layer. Beneath this outermost layer is a band of electron-dense material, consisting of densely packed granules and is half as thick as the outer particulate layer. The 3rd layer consists of relatively thick, weakly laminated chorion, with a felt-like appearance due to a meshwork of microfibrils. Projections of this network of microfibrils form pillars that attach this layer to a thin relatively compact 4th or basal layer. The pillars and the air-filled cavities lying between the 3rd and 4th chorionic layers constitute the chorionic meshwork known as the palisades or trabecular layer that form the major respiratory organ of the eggshell. The trabecular layer is connected to the external environment by means of the lateral and anterior aeroplyes. The vitelline membrane lies between the chorion and oocyte and is a granular, uniform, moderately electron-dense layer measuring approximately 260 nm thick. The micropyle at the posterior of the flea egg consists of a rosette of 50-80 apertures and possesses an internal electron-dense plug between the chorion and the vitelline membrane. An aeropyle at the anterior end of the egg consists of a rosette of 40-50 apertures. An inconspicuous aeropyle appears as a cluster of hexagonal or polygonal-shaped plaques on the lateral surface of the chorion. Each plaque contains 3-8 pores.
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Plague occurs episodically in many parts of the world, and some outbreaks appear to be related to increased abundance of rodents and other mammals that serve as hosts for vector fleas. Climate dynamics may influence the abundance of both fleas and mammals, thereby having an indirect effect on human plague incidence. An understanding of the relationship between climate and plague could be useful in predicting periods of increased risk of plague transmission. In this study, we used correlation analyses of 215 human cases of plague in relation to precipitation records from 1948 to 1996 in areas of New Mexico with history of human plague cases (38 cities, towns, and villages). We conducted analyses using 3 spatial scales: global (El Niño-Southern Oscillation Indices [SOI]); regional (pooled state-wide precipitation averages); and local (precipitation data from weather stations near plague case sites). We found that human plague cases in New Mexico occurred more frequently following winter-spring periods (October to May) with above-average precipitation (mean plague years = 113% of normal rain/ snowfall), resulting in 60% more cases of plague in humans following wet versus dry winter-spring periods. However, we obtained significant results at local level only; regional state-wide precipitation averages and SOI values exhibited no significant correlations to incidence of human plague cases. These results are consistent with our hypothesis of a trophic cascade in which increased winter-spring precipitation enhances small mammal food resource productivity (plants and insects), leading to an increase in the abundance of plague hosts. In addition, moister climate conditions may act to promote flea survival and reproduction, also enhancing plague transmission. Finally, the result that the number of human plague cases in New Mexico was positively associated with higher than normal winter-spring precipitation at a local scale can be used by physicians and public health personnel to identify and predict periods of increased risk of plague transmission to humans.
Article
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The seasonal occurrence of Ctenocephalides felis felis (Bouché and Ctenocephalides canis (Curtis) infestation on dogs and cats in Cuernavaca City in Mexico, was determined by examining 1,803 dogs and 517 cats at two veterinary clinics during 1995-1997. The overall flea infestation was 30.3 and 30.1% for dogs and cats, respectively. There were no significant differences (P > 0.05) in percentage of infestation among years for both hosts. The infestation was somewhat higher in spring, summer, and autumn than in winter, but no statistical differences was found among seasons (P > 0.05) for both pets. No relationship existed between percentage of flea infestation and temperature or rainfall among seasons. On dogs, 81.1% were infested with only C. felis felis, 16.8% with C. canis, and 2% had both flea species; whereas 92.3% of the cats were infested with C. felis felis and 7.7% with C. felis felis and C. canis. The cat flea was the most prevalent flea species found other than C. canis; no other species were found on the dogs and cats. It appeared that flea life cycle development continued throughout the year.
Article
To counteract water loss due to excretion, cuticular transpiration and respiration, various groups of arthropods have developed mechanisms for active uptake of water vapor from unsaturated air. In this study, active uptake capabilities and water loss rates were examined in the various developmental stages of the cat flea, Ctenocephalides felis. To determine critical equilibrium humidity, the lowest relative humidity at which active water uptake can occur, pre-desiccated immature and adult fleas were placed in a series of humidity regimes ranging from 44 to 93% RH. Active uptake occurred in larval stages at relative humidities above 53% and in pre-pupae at 75-93% RH. Pupae and adults did not demonstrate active uptake at any humidity. Optimal uptake for larvae occurred between 20 and 30 degrees C. When placed over Drierite (<10% RH), larval and adult stages demonstrated a higher rate of water loss than pre-pupal and pupal stages. Active water uptake is necessary to ensure proper development of the larvae of C. felis. Active uptake ceases after the larval-pupal ecdysis and it appears that adults have lost the ability to actively uptake water.
Article
From an ongoing country-wide study on the spectrum, the epidemiology and the population dynamics of flea infestations in dogs and cats, important preliminary results from the three areas of Karlsruhe, Nuernberg and Leipzig are presented. A total of 1922 dogs and 1838 cats from 12 different veterinary practices or clinics in three areas of Germany were systematically examined between July 2003 and June 2004. All dogs and cats appearing for a clinical veterinary consultation on one regular working day per month, per practice, were clinically examined. Dogs and cats were examined irrespective of any kind of prior therapeutic or prophylactic insecticidal treatment. The results show that a total of 99 dogs (5.13%) and 263 cats (14.33%) were infested. Cats were more often flea-infested than dogs (p < 0.05). The highest infestation rates for dogs (x = 7.87%) were detected between July and October, and for cats (x = 21.14%) between July and September, the lowest infestation rates for dogs (x = 2.88%) were observed between November and May, and for cats (x = 12.16%) between November and April (p < 0.05). Although the prevalences were generally higher during the summer months, no statistical differences were detectable when looking at the pattern between the four seasons, neither for dogs, nor for cats. Interestingly, the highest prevalences in dogs (9.9%) were detected in June 2004 and comparatively, in cats (23.86%) in August. The lowest detection rates in dogs were seen (1.28%) in April and in cats (7.26%) in January. The preliminary results did not indicate any tendency for a relationship between climatic conditions and flea infestation rates. Similarly, no differences of the infestations rates were detectable between urban and rural areas, 56% (dogs) and 46% (cats) of the infested pets originated from urban habitats. The flea species collected include Ctenocephalides felis, Ctenocephalides canis, Archaeopsylla erinacei, Pulex irritans, Ceratophyllus gallinae, etc. The overall frequencies reveal that C. felis was the most prominent species (81.5%), followed by C. canis (12.5%), A. erinacei (2.7%) and P. irritans (1.7%).
Article
Fleas are wingless insects that parasitize mammals and more rarely birds. They are able to jump and may bite people. Adult fleas are hematophagous. The impact of fleas on public health is related to their ability to act as vectors for transmission of infectious agents during blood meals. The purpose of this article is to describe fleas and the diseases that they transmit to humans. Special focus is placed on epidemiological aspects.
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Five species belonging to 4 genera of fleas were found on Egyptian dogs. They were Ctenocephalides felis felis (Bouché 1835) (9,008 specimens), Pulex irritans (Linnaeus 1758) (1,090 specimens), Ctenocephalides canis (Curtis 1826) (549 specimens), Echidnophaga gallinacea (Westwood 1875) (29 specimens), and Xenopsylla cheopis (Rothschild 1903) (6 specimens). The first 3 species were the most common on dogs in all regions investigated and the only ones collected in the dense metropolis of Cairo and Giza where seasonal dynamics were studied.
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The survival and development of the cat flea, Ctenocephalides felis, were assessed at various temperatures and relative humidities (RH). The upper and lower temperature limits for development (egg to adult) were 32 and 13°C. The length of the developmental period ranged from 14 to 140 days at these temperature extremes. Complete development occurred from 50–92% rh. Immature C. felis reared at 92% rh produced larger adults than those reared at 50% rh. At 27°C, the minimum rh necessary for greater than 50% survival of the immature stages was egg, 33%; larva, 50%; and pupa, 2%. Adult longevity increased with increasing rh and decreasing temperature.
Article
Previous efforts to control insects by means of desiccating dusts have been directed primarily against granary weevils and with abrasive materials. Drywood termites were found to be more susceptible to sorptive than to abrasive dusts. By means of a staining technique it was shown that sorptive dusts can remove the lipoid protective layer covering the epicuticle, causing the termites to lose water rapidly. The insects needed only to crawl about on a thin film of the dust. They died after losing about 30% of their body weight in water. Certain silica aerogels were particularly effective. Other insects, including cockroaches, fleas, bedbugs, bees, ants, vinegar flies, mosquitoes, house flies, thrips, ticks and mites, likewise succumbed rapidly to desiccation initiated by the disruption or removal of the lipoid protective layer by sorptive dusts. Although some conventional insecticides might cause more rapid knockdown, they never resulted in death of the insects tested as rapidly as the more effective desiccating dusts. Certain water-soluble fluorides have been incorporated into the silica areogels in the process of manufacture. These fluorides greatly increase the effectiveness of the impregnated aerogels, even at low relative humidities, but the advantage obtained from the impregnation increases with increasing relative humidities and consequently increases the versatility of the silicas. The presence of fluorides as monomolecular layers in the porous silica aerogel particles does not decrease the ability of these particles to adsorb wax. After the wax is adsorbed or disrupted, the water-soluble fluorides can act as contact insecticides. In addition, the strong positive charge they impart to the particles greatly increases their ability to adhere to the dusted surfaces. The addition of surface-active solutes to petroleum oil will cause increased rate of water loss, the water appearing in the form of many small droplets. Desiccation is greatly enhanced when the applied oil is later removed and the insect cuticle is thereby directly exposed to air. Death may result more rapidly than by the toxicity or suffocation that takes place when the insects are completely immersed in oil. Desiccation of drywood termites was caused by treatment with parathion, sodium fluoride, and anhydrous magnesium perchlorate. When the treated insects, as well as those shaken in a sorptive dust, were immersed in oil, water droplets appeared on the body surfaces.
Article
This paper is the result of a series of studies on the nutritional and environmental requirements of the cat flea, Ctenocephalides felis Bouché made in an effort to determine some of the fundamental biological necessities of the species.
Article
Partially dehydrated third-stage larvae of Xenopsylla cheopis take up water vapour from the air after transference to higher humidities. A net uptake of vapour occurs at relative humidities from close to saturation down to 65 per cent r.h., the critical equilibrium humidity. The amount of vapour taken up from the air, until the larvae achieve equilibrium, is greater the higher the relative humidity (Fig. 1); the larvae maintain this equilibrium at a high environmental humidity with a high water content and at a lower humidity with a lower water content. At 93 per cent r.h. and 25°C water vapour is transported from the air into partially dehydrated larvae at an approximately constant rate of 11 μg/hr per larva or 2·0 μg/hr per mm2 surface area and continuously for an average period of 6 hr until the equilibrium water content is achieved. The uptake curve, then, rather abruptly takes a horizontal course (Fig. 2); water loss and water uptake become balanced and the starving larvae remain unchanged in weight for 24 to 48 hr. Water is transferred faster into partially dehydrated larvae the higher the humidity to which the larvae are exposed. The rate of transpiration at 0 per cent r.h. and 25°C is 4·7 μg/hr per larva or 0·9 μg/hr per mm2 surface area. Net sorption of vapour from almost saturated air is approximately twice as fast as transpiration into dry air.
Article
Sensitization of guinea pigs to flea bites, by exposure to the bites of Pulex irritans, P. simulans and Ctenocephalides felis felis, resulted in a delayed 12 to 24-hour reaction. The development of hypersensitivity and resulting lesions very closely duplicated the early phases of sensitivity in human beings subjected to intradermally injected foreign proteins or to the bites of insects such as mosquitoes or blackflies. The present results differed sharply from the reported results of experimental sensitization of rabbits to the bites of various mosquitoes.Guinea pigs sensitized to one species of flea as a rule reacted to all flea species used in the experimental work reported here. This would seem to indicate the presence of a common antigenic factor present in P. irritans, P. simulans, and C. f. felis.
Article
Clinical signs of acute fleabite allergic dermatitis (FAD) in dogs included intense pruritus and erythema. Dogs with chronic FAD had diminished pruritus. The primary lesion of FAD was a papule. Secondary lesions (hyperkeratosis and hyerpigmentation) were common. Diagnosis of FAD was based on history of flea infestation and on type and location of lesions. Intradermal testing with glycerinated flea antigen was of little diagnostic value. Treatment of FAD included (1) breaking the flea life cycle in the indoor and kennel environment by vacuuming and washing bedding as well as by the use of aerosol insecticides for fumigation, (2) minimizing flea infestation on the dogs by using insecticidal dips, baths, and flea collars, and (3) hyposensitization with flea antigen.
Article
This is the first of a series of papers in summation of our current knowledge of flea distribution relative to both land masses and hosts. Evaluation is carried to the species level and the organization of the paper permits its utilization as a check-list of the genera and species of fleas. All known members of the family Pulicidae are treated.
Article
In his comprehensive monograph on plague, published by WHO in 1954, Dr Pollitzer pointed out that despite the marked drop in the incidence of this disease in recent years, he considered it impossible for various reasons to be complacent about the situation. Since this monograph appeared, plague has shown a truly spectacular decrease, but in case this is partly the outcome of a natural periodicity of the infection, the author still feels that the disease "should be given continued attention by those interested in global public health". To this end he summarizes here the latest information on the subject, his review covering not only works published since 1954, but also some earlier literature (particularly from the USSR) which was not available to him at the time of preparation of his monograph.
An illustrated catalogue of the Rothschild collection of fleas in the British Museum
  • G H E Hopkins
  • M Rothschild
Hopkins, G. H. E., and M. Rothschild. 1953. An illustrated catalogue of the Rothschild collection of fleas in the British Museum. Vol. I. University Press, Cambridge. 361 pp.
Loppeallergi hos hund og kat. Dansk Vet
  • S Kristensen
Kristensen, S. 1976. Loppeallergi hos hund og kat. Dansk Vet. Tidsskr. 59: 553-560.
Rat and rat-flea survey of Los Angeles Harbor
  • H E Trimble
  • G C Sherrard
Trimble, H. E., and G. C. Sherrard. 1935. Rat and rat-flea survey of Los Angeles Harbor. Pub. Health Rep. 50: 74-79.