Number Of Fleas Research Articles

Space matters: host spatial structure and the dynamics of plague transmission

The development of models to elucidate the transmission pathways and dynamics of wildlife diseases remains challenging. Sylvatic plague, caused by the bacterium Yersinia pestis (Yp), is an infectious zoonotic disease that primarily affects wild rodents, including prairie dogs (Cynomys spp.) in North America. Proposed transmission pathways for Yp include flea bites, direct contacts between hosts, and environmental reservoirs (e.g. soil, carcasses). We developed a spatially explicit, agent-based model of Yp transmission to explore the effects of alternative transmission pathways, different disease initiation mechanisms (host or fleas), parameter uncertainty, and spatial structure of hosts. A particularly novel aspect of our model was the integration of ecological models with traditional disease models. Specifically, we used estimates from spatial capture-recapture models to generate data-driven spatial distributions, densities, and contact rates to capture the spatial structure of prairie dogs. We simulated ~9 million scenarios across a wide range of parameter values and conducted sensitivity analyses to determine the most influential parameters on the number of flea-days (sum of the mean number of fleas on hosts each day of the simulation), number of newly infected hosts per day, the time to depopulation (<20 prairie dogs remaining), and the proportion of the prairie dog population remaining at the end of the simulation (after 150 days). When including spatial structure, we found the probability of transmission via environmental sources of Yp (i.e. carcasses) had the greatest influence on model results when Yp infection was initiated in prairie dog hosts, rather than in fleas. Conversely, the mechanism of transmission by fleas to prairie dogs had the greatest influence on model results when Yp infection was initiated in fleas (i.e. via introduction by carnivores, a migrant prairie dog, or other mammalian host). Uncertainty in parameter estimates, particularly those related to the transmission pathways of Yp, continue to hamper efforts to realistically model plague dynamics in wild rodents. Our results elucidate the complexity of the flea-plague-prairie dog system and reiterate the importance of research on Yp transmission mechanisms to provide a full understanding of this disease. Our results also emphasize the importance of realistic estimates of spatial structure for exploring transmission dynamics of wildlife diseases and provide a framework for generating a data-driven description of spatial structure.

Efficacy of a novel topical combination of esafoxolaner, eprinomectin and praziquantel against fleas in cats, under field conditions.

Esafoxolaner is a purified afoxolaner enantiomer with insecticidal and acaricidal properties. It is combined with eprinomectin and praziquantel, nematodicidal and cestodicidal compounds, in a novel topical endectoparasiticide formulation for cats. This novel formulation was tested in four field studies, in the United States, Europe, Japan and Australia. In all studies, naturally flea-infested domestic cats were treated with the novel formulation at the label dose and conditions of use. The main objective, identical in the four studies, was to assess efficacy on fleas, based on comparison of mean number of fleas found on infested cats before and one month after treatment. Tolerance to the product was also evaluated in the four studies. Otherwise, the studies had some differences in their design and secondary objectives, for example testing for a reduction in flea infestation-related cutaneous signs, testing of one treatment or of three monthly treatments, and use of a positive control group. In the four studies, a total of 307 cats were treated with the novel formulation. The reduction of fleas one month after treatment was 97.7%, 98.8%, 100% and 99.7% in the United States, Europe, Japan and Australia, respectively. There were no significant health abnormalities attributed to treatment in any of the studies.

Flea Communities on Small Rodents in Eastern Poland.

Simple SummaryFleas are obligatory, secondarily wingless, hematophagous insects living all over the world. They colonize a variety of habitats from wet tropical forests to semi-arid and desert areas. Adult individuals feed mainly on small mammals, and less often on birds. The aim of the present study was to explore the fauna of fleas and their broad-sense behavior in eastern Poland. Rodents, which are widely recognized as one of the preferred hosts of these insects, were caught to carry out the study. The results show that, regardless of the ecological habitat type, the striped field mouse Apodemus agrarius was the most frequently captured rodent species, and the Ctenophthalmus agyrtes flea species was collected most frequently. Moreover, rhythms in the seasonal activity of fleas, with a peak in summer months, were noted.Fleas are hematophagous insects infesting mainly small mammals and, less frequently, birds. With their wide range of potential hosts, fleas play a significant role in the circulation of pathogens in nature. Depending on the species, they can be vectors for viruses, bacteria, rickettsiae, and protozoa and a host for some larval forms of tapeworm species. The aim of this study was to determine the species composition of fleas and their small rodent host preferences in eastern Poland. Animals were captured in traps in various types of ecological habitats (a site covered by grassland vegetation within city limits, an unused agricultural meadow, and a fallow land near a mixed forest). The following rodent species were caught: Apodemus agrarius, Apodemus flavicollis, Microtus arvalis, and Myodes glareolus. Additionally, Ctenophthalmus agyrtes, Ctenophthalmus assimilis, Hystrichopsylla talpae, and Nosopsyllus fasciatus flea species were identified. The peak of the flea activity was noted in summer months. C. agyrtes was found to be the most abundant flea species in eastern Poland, while the greatest numbers of fleas were collected from the rodent species A. agrarius.

Comparison of the transmission efficiency and plague progression dynamics associated with two mechanisms by which fleas transmit Yersinia pestis.

Yersinia pestis can be transmitted by fleas during the first week after an infectious blood meal, termed early-phase or mass transmission, and again after Y. pestis forms a cohesive biofilm in the flea foregut that blocks normal blood feeding. We compared the transmission efficiency and the progression of infection after transmission by Oropsylla montana fleas at both stages. Fleas were allowed to feed on mice three days after an infectious blood meal to evaluate early-phase transmission, or after they had developed complete proventricular blockage. Transmission was variable and rather inefficient by both modes, and the odds of early-phase transmission was positively associated with the number of infected fleas that fed. Disease progression in individual mice bitten by fleas infected with a bioluminescent strain of Y. pestis was tracked. An early prominent focus of infection at the intradermal flea bite site and dissemination to the draining lymph node(s) soon thereafter were common features, but unlike what has been observed in intradermal injection models, this did not invariably lead to further systemic spread and terminal disease. Several of these mice resolved the infection without progression to terminal sepsis and developed an immune response to Y. pestis, particularly those that received an intermediate number of early-phase flea bites. Furthermore, two distinct types of terminal disease were noted: the stereotypical rapid onset terminal disease within four days, or a prolonged onset preceded by an extended, fluctuating infection of the lymph nodes before eventual systemic dissemination. For both modes of transmission, bubonic plague rather than primary septicemic plague was the predominant disease outcome. The results will help to inform mathematical models of flea-borne plague dynamics used to predict the relative contribution of the two transmission modes to epizootic outbreaks that erupt periodically from the normal enzootic background state.

The Role of Disinsection and Deratization in the Framework of Non-Specific Prophylaxis of Diseases among the Population in Natural Plague Foci in the Territory of the CIS Countries

Natural foci of plague – a particularly dangerous transmissible zoonotic disease – are widely spread across the world, including in the territory of Russia and a number of neighboring countries in Central Asia. Between 2000 and 2019, 28339 cases of plague were registered in 21 states around the world; lethality rates reached 8 %. Active plague manifestations are associated with the increase in the abundance of carriers and vectors of the disease, which increases the risk of human infection. Prophylactic measures against plague are aimed at prevention and eradication of epidemic foci; they incorporate a whole complex (system) of activities. Disinsection and deratization remain the most radical of them. Control of the numbers of carriers and vectors of plague involves decrement up to the levels at which epizooties will not develop, they are suppressed and liquidated. Currently in the Russian Federation and CIS countries, the focus is on the field and community disinsection when planning and performing exterminatory interventions. The decrease in the numbers of fleas – carriers and vectors of plague microbe – results in disruption of epizootic process and, consequently, in provision of epidemiological welfare as regards this dangerous disease. Insecticide treatments in natural biotopes are carried out using powder-like or aerosolized products, the class of pyrethroids, organophosphorous compounds and phenylpyrazoles by means of advanced equipment: knapsack dusters, power operated air blowers, and foggers. Within the boundaries of residential areas wet disinsection is performed with the help of spraying devices. Field deratization is allowed upon epidemiological grounds only, in localized territories of epizooties, within the boundaries of the settlements of plague infected carriers. Zinc phosphide- or anticoagulant-based bait products are used as rodenticides. Therewith, the eradication of valuable animal species, rare species of small mammals and endemic species is prohibited. Community deratization is always accompanied by the community disinsection. When planning and carrying out insecticide and rodenticide treatments the priority is given to the safety of handling the chemical preparations, to the exclusion of the negative effect on target animal species.

The relationship between fleas and small mammals in households of the Western Yunnan Province, China

The Yunnan province has one of the most serious outbreaks of the plague epidemic in China. Small mammals and fleas are risk factors for the occurrence of plague in commensal plague foci. Understanding the relationship between fleas and small mammals will help control fleas and prevent the onset of the plague. Four hundred and twenty-one small mammals, belonging to 9 species, were captured. Of these, 170 small mammals (40.4%) were found infested with fleas. A total of 992 parasitic fleas (including 5 species) were collected. The number of Leptopsylla segnis and Xenopsylla cheopis accounted for 91.03% (903/992). The final multiple hurdle negative binomial regression model showed that when compared with Rattus tanezumi, the probability of flea infestation with Mus musculus as well as other host species decreased by 58% and 99%, respectively, while the number of flea infestations of the other host species increased by 4.71 folds. The probability of flea prevalence in adult hosts increased by 74%, while the number of fleas decreased by 76%. The number of flea infestations in small male mammals increased by 62%. The number of fleas in small mammals weighing more than 59 g has been multiplied by about 4. R. tanezumi is the predominant species in households in the west Yunnan province, while L.segnis and X. cheopis were dominant parasitic fleas. There is a strong relationship between the abundance of fleas and the characteristics of small mammals (e.g. Species, age, sex, and body weight).

Effect of a combination of permethrin and diesel oil on &lt;i&gt;Rhipicephalus sanguineus&lt;/i&gt; and &lt;i&gt;Ctenocephalides canis&lt;/i&gt; in experimentally infested dogs

Rhipicephalus sanguineus (Brown dog tick) and Ctenocephalides canis (dog and cat flea) cause heavy economic burden for dog owners in Nsukka, south-east, Nigeria, and are also major cause of vector-borne diseases worldwide. A total of 40 apparently healthy dogs were randomly assigned to 3 groups (A, B and C) and experimentally infested with Rhipicephalus sanguineus and Ctenocephalides canis. Each dog in Group A (n = 10) was treated with a mixture of permethrin and diesel oil while Groups B (n = 6) and C (n = 4) were treated with permethrin and diesel oil respectively. The remaining dogs in each group served as controls. Parasites were counted 48th hour post-treatment and efficacy estimated as percentage reduction in live parasites in treated groups compared to untreated groups. In Group A the average percentage efficacy was 99.7% while in groups B and C it was 98.3% and 72.1% respectively for R. sanguineus, Geometric mean of live parasites between treated and control groups was significantly different (p&lt;0.05) for every day in Groups A, B and C. Tick and flea numbers can be reduced in dogs by the application of diesel oil as an acaricide.&#x0D; Keywords: Dogs; tick and flea control; diesel fuel oil; permethrin.

Laboratory studies evaluating the efficacy of a novel orally administered combination product containing sarolaner, moxidectin and pyrantel (Simparica Trio\u2122) for the treatment and control of flea infestations on dogs

BackgroundFive studies were conducted to evaluate a novel oral combination tablet containing sarolaner, moxidectin and pyrantel (Simparica Trio™), for efficacy against induced flea infestations, speed of kill and effects on flea reproduction on dogs.MethodsBased on pre-treatment flea counts, dogs were randomly allocated to treatment with a single, oral dose of either placebo or Simparica Trio™ at the minimum label dose of 1.2 mg/kg sarolaner, 24 µg/kg moxidectin and 5 mg/kg pyrantel (as pamoate salt) on Day 0. All dogs were infested with approximately 100 unfed, adult fleas (C. felis or C. canis) prior to treatment and weekly for 5 weeks post-treatment. In Studies 1, 2 and 3, the number of viable fleas were comb-counted at 24 h after treatment and after each weekly infestation; Study 2 also included groups treated with tablets containing sarolaner-alone (1.2 mg/kg), moxidectin-alone (24 µg/kg) or pyrantel-alone (5 mg/kg). In Study 4, flea counts were conducted at 3, 4, 8 and 12 h after treatment and subsequent weekly infestations to establish speed of kill. In Study 5 (flea reproduction), dogs were housed in an enclosure designed to facilitate collection of flea eggs.ResultsEfficacy of Simparica Trio™ against C. felis was ≥ 99.7% and against C. canis was 100% at 24 h after treatment and after subsequent infestations for at least 35 days. Treatment with sarolaner-alone had similar efficacy to Simparica Trio™, while moxidectin-alone and pyrantel-alone were no different from placebo at most time points. In Study 4, significant flea killing started at 4 h after treatment; by 8 h after treatment, all treated dogs were free of fleas. Following weekly re-infestation, the combination product reduced fleas by ≥ 97.8% within 12 h for 28 days. Simparica Trio™ reduced flea egg-laying by 100% for 35 days. No treatment-related adverse reactions occurred in any study.ConclusionsA single dose of Simparica Trio™ at the recommended minimum dose provided highly efficacious and rapid treatment within 4 h of existing flea infestations and persistent control of fleas on dogs for 5 weeks. The efficacy against fleas resulted in 100% prevention of flea reproduction for over a month following a single oral dose.

Flea sharing among sympatric rodent hosts: implications for potential plague effects on a threatened sciurid

AbstractFor vector‐borne diseases, the abundance and competency of different vector species and their host preferences will impact the transfer of pathogens among hosts. Sylvatic plague is a lethal disease caused by the primarily flea‐borne bacterium Yersinia pestis. Sylvatic plague was introduced into the western United States in the early 1900s and impacts many species of rodents. Plague may be suppressing populations of the threatened northern Idaho ground squirrel (Urocitellus brunneus) if a competent flea community is allowing plague to be maintained within the few extant sites that support this rare ground squirrel. We collected fleas from four species of sympatric rodents in central Idaho: northern Idaho ground squirrels, Columbian ground squirrels (Urocitellus columbianus), yellow‐pine chipmunks (Tamias amoenus), and deer mice (Peromyscus maniculatus). We evaluated which flea species were present and whether fleas were shared among the rodent community. We documented seven species of fleas among 3356 fleas collected from the four host species of rodents, and all seven species of fleas are known vectors of plague. Three of the seven flea species were detected on all four rodent species, demonstrating potential for spillover of plague (bridge vectors) in the rodent community. We used generalized linear mixed models to evaluate which abiotic and biotic factors influence flea abundance (total number of fleas, regardless of flea species, on each individual host of the four rodent host species). Factors that impacted flea abundance varied among the four host species, but flea abundance: (1) changed over summer depending on host species, (2) was greater on males, and (3) was impacted by summer and winter precipitation depending on host species. Our results suggest this diverse flea community has the capacity to transfer Y. pestis among populations of the four rodents if Y. pestis is present. Furthermore, the disease may be more likely to persist in some locations than others, those that have higher flea abundances, more sympatric hosts, or optimal conditions for fleas, and such high‐risk sites can be identified based on their abiotic and biotic factors.

Effect of host and environment-related factors on fleas of the pichi, an armadillo from Argentina.

The pichi (Zaedyus pichiy; Cingulata: Chlamyphoridae) is an armadillo whose ectoparasite fauna is composed of ticks and fleas. Fleas were collected from 218 pichis in southern Mendoza, Argentina, in summer and winter of 2015 and 2016. Prevalences were analyzed and differences in the intensities of the total number of fleas related to host (age, sex, weight, size and physical condition) and environment-related (seasonality and year) factors evaluated. Phthiropsylla agenoris was the only species found. Intensities of fleas were higher in 2015, in juveniles, and in males. Individuals with poor physical condition were more parasitized than those with good or normal body condition. The main explanatory variable was sampling year. This factor was directly associated with precipitation. The extreme conditions and heavy rains during the El Niño event in 2015/2016 led to environmental changes that seem to have severely affected the life cycle of fleas.

Drought-induced spatio-temporal synchrony of plague outbreak in Europe

Plague synchronously swept across separated regions in Europe throughout history. However, the spatio-temporal synchrony of plague and its driving mechanism have not been thoroughly investigated. In this study, we transformed the historical European plague database spanned 1347–1800 CE into country-level time-series that differentiated large-scale plague outbreak from counted data. We found that there are 74 years in which two or more countries in our study region (UK, France, Germany, Spain, and Italy) experienced large-scale plague outbreak in the same year. Our Multivariate Ripley's K-function results showed that the onset year and the cessation year of large-scale plague outbreak are synchronized at the 0–23-year and 0–20-year windows, respectively. The temporal association between such synchrony and climatic forcing was further investigated using the Superposed Epoch Analysis, and drought was found to be responsible for the synchrony. Integrating our results with a literature survey, we suggested that prior to the peak of plague, the occurrence of drought and the subsequent reintroduced rainfall dampened both the rodent community and human society and boosted the number of fleas that carried plague. Such a synthesis facilitated the outbreak of plague. At the same time, high temperature associated with such drought also confined the geographic diffusion of the plague. Hence, although continental mega-drought could initiate the synchrony of plague outbreak, the synchrony actually consisted of a number of localized plague outbreak events scattering across different regions in Europe. According to the projected rising trend of drought in terms of its magnitude, duration, and geographic extent, the risk of synchrony of rodent-borne diseases in Europe will be significantly elevated, especially in France, Italy, and Spain.

Fleas of black rats (Rattus rattus) as reservoir host of Bartonella spp. in Chile.

BackgroundRattus rattus is a widely distributed, invasive species that presents an important role in disease transmission, either directly or through vector arthropods such as fleas. These black rats can transmit a wide variety of pathogens, including bacteria of the genus Bartonella, which can cause diseases in humans and animals. In Chile, no data are available identifying fleas from synanthropic rodents as Bartonella vectors. The aim of this study was to investigate the prevalence of Bartonella spp. in the fleas of R. rattus in areas with different climate conditions and featuring different human population densities.MethodsIn all, 174 fleas collected from 261 R. rattus captured from 30 localities with different human densities (cities, villages, and wild areas) across five hydrographic zones of Chile (hyper-arid, arid, semi-arid, sub-humid, and hyper-humid) were examined. Bartonella spp. presence was determined through polymerase chain reaction, using gltA and rpoB genes, which were concatenated to perform a similarity analysis with BLAST and phylogenetic analysis.ResultsOverall, 15 fleas species were identified; Bartonella gltA and rpoB fragments were detected in 21.2% (37/174) and 19.5% (34/174) of fleas, respectively. A total of 10 of the 15 fleas species found were positive for Bartonella DNA. Leptopsylla segnis was the most commonly collected flea species (n = 55), and it also presented a high prevalence of Bartonella DNA (P% = 34.5%). The highest numbers of fleas of this species were collected in villages of the arid zone. There were no seasonal differences in the prevalence of Bartonella DNA. The presence of Bartonella DNA in fleas was recorded in all hydrographic areas, and the arid zone presented the highest prevalence of this species. Regarding areas with different human densities, the highest prevalence was noted in the villages (34.8% gltA and 31.8% rpoB), followed by cities (14.8% gltA and 11.1% rpoB) and wild areas (7.4% gltA and 14.8% rpoB). The BLAST analysis showed a high similitude (>96%) with four uncharacterized Bartonella genotypes and with two species with zoonotic potential: B. mastomydis and B. tribocorum. The phylogenetic analysis showed a close relationship with B. elizabethae and B. tribocorum. This is the first study to provide evidence of the presence of Bartonella in fleas of R. rattus in Chile, indicating that the villages and arid zone correspond to areas with higher infection risk.

The Existence of Fleas in Rodents at Plague Observation Area in Nongkojajar Pasuruan District

The existence of rodents and vectors are still a critical threat for human life and public health due to its potentials in transmitting diseases. Rodents, especially rats are the main source of plague transmission, leptospirosis, rickettsiosis, and nematode worms are also a fleas host as a carriers vector of bacteria cause plague and rickettsiosis. This study aimed to identify the number and types of rats and fleas in the plague observation area in Nongkojajar Sub District, Pasuruan District. This research was an observational study with time series design. The researcher used secondary data from Environmental Health Technology and Development Bureau (BBTKLPP) Surabaya in Epidemiology Surveillance Division. The population was all rats and fleas caught in during 2014-2018. This study was held on October 2018 in Surabaya. The data was presented in the form of tables and graphs. Rats caught from 2014-2018 were mostly indoor rats in the house. Results of rats sweeping found two types of main fleas in majority, the number of Xenopsylla cheopis was higher than Stivalius cognatus. Analysis data at week 4-26 in 2018 found the most of rats caught were the types of Rr. diardi, then R. exulans, S. murinus H. suilus, and other types of rats. Most caught type of rats in the area of PES observation in Nongkojajar Pasuruan was Rr. diardi in the house. Most type of fleas found is Xenopsylla cheopis. The conclusion of this study: It is recommended to strengthen vector control and monitoring program in Nongojajar order to avert the elevated incidence cases of plague, leptospirosis, rickettsia and nematoda.

Efficiency of the application of insectofungicide prestige for grain crops protection against harmful organisms

The effectiveness of the insecticofungicide Prestige, KS, used to protect plants from damage by diseases and damage by pests in the first stages of ontogenesis is shown. Presowing seed treatment with a preparation with a flow rate of 2.5–3.5 l/t reduced the incidence of winter wheat with root rot of rhizoctoniosis etiology by 62.9%. The biological effectiveness of the Prestige, KS (3.5 l / t) on moderately infectious background was also quite high - 59.5%, however, it was 9.0% lower than the standard. It practically did not influence overwintering of plants. After application of Prestige, KS were in the norm of 2.5 and 3.5 l/t, and Maxim Extreme, KS in the norm of 1.75 l/t, the number of plants preserved by spring varied from 91.9 to 92.9%, that is higher than in the control by 3.9–4.9%. The application of insectofungicide Prestige, KS at a rate of 2.5 l/t on spring wheat sowings reduced the number of grain fleas by more than 80.0%and the damage of the stems by the larvae of cereal flies by 74.3%. This preparation is not phytotoxic with respect to cereals.

Plague management of prairie dog colonies: degree and duration of deltamethrin flea control

Plague is a flea-borne disease of mammalian hosts. On the grasslands of western North America, plague stifles populations of Cynomys spp. prairie dogs (PDs). To manage plague, PD burrows are treated with 0.05% deltamethrin dust that can suppress flea numbers and plague transmission. Here, we evaluate the degree and duration of deltamethrin flea control with three PD species at six sites across four U.S. states. Data were simultaneously collected at paired plots. Burrows from one randomly assigned member of each pair were treated with deltamethrin; non-treated plots served as experimental baselines. Flea control was strong ≤two months after treatment, remained moderate one year later, and was statistically detectable for up to two years at some sites. Flea abundance was lower in plots with higher rates of deltamethrin application. After burrow treatments, flea abundance increased over time, reaching >one per PD within 255 to 352 days. Nevertheless, annual treatments of burrows with deltamethrin provided PDs with substantial protection against plague. Even so, deltamethrin should be further evaluated and combined with other tools under an integrated approach to plague management. Integrated plague management should help to conserve PDs and species that associate with them, including the endangered black-footed ferret (Mustela nigripes).

Mediterranean Eucalyptus plantations affect small mammal ectoparasites abundance but not individual body condition

AbstractBiodiversity is recognizably affected by land conversion for agriculture. However, the assessment of impacts on wildlife often lacks information on populations structure and individuals' condition, allowing only a limited view of the problem. Individual body condition/health can influence animal's reproductive success or survival. Eucalyptus globulus plantations are important forestry systems in Iberia, being the widest forested‐land use in Portugal, which hosts the broadest European E. globulus coverage. We tested Eucalyptus plantations' effects on small mammals' body condition (using the Scaled Mass Index‐SMI as surrogate) and ectoparasite abundance (number of mites, ticks and fleas per host). We applied a Generalized Linear Mixed Model (GLMM) approach for testing the influence of gender, habitat, species, season and understory cover on SMI and ectoparasites abundance. We captured 681 individuals, hosting overall 521 fleas (n = 305), mites (n = 159) and ticks (n = 57). Animal's body condition was not affected by plantations, but was lower for males and higher in spring. However, animals captured in Eucalyptus plantations and spring had higher parasite abundance (namely ticks and fleas), as well as males. Mites results were inconclusive. Body condition patterns seem to be determined by males demanding spatial/reproductive behavior (i.e., wider home‐ranges and search for females), while plantations promote ectoparasites abundance (e.g., induced by habitat disturbance and dilution effect). Results highlight that plantations may have negative effects on wildlife, but the evaluation of anthropic landscapes impact upon wildlife should encompass several bio‐ecological indicators, since the use of a restricted set (e.g., body condition) may induce a biased view.

Host biology and environmental variables differentially predict flea abundances for two rodent hosts in a plague-relevant system.

While rodents frequently host ectoparasites that can vector zoonotic diseases, often little is known about their ectoparasite communities, even in places where hosts frequently interact with humans. Yosemite National Park is an area of high human-wildlife interaction and high potential zoonotic disease transfer. Nonetheless, relatively few studies have surveyed the flea communities on mammalian hosts in this area, and even fewer have characterized the environmental and host factors that predict infestation. We focused on two species, the alpine chipmunk (Tamias alpinus) and the lodgepole chipmunk (T. speciosus), which inhabit Yosemite and surrounding areas and can host fleas that vector plague. Because these hosts are exhibiting differential responses to environmental change, it is valuable to establish baselines for their flea communities before further changes occur. We surveyed fleas on these chipmunk hosts during three years (2013–2015), including in the year of a plague epizootic (2015), and documented significant inter-host differences in flea communities and changes across years. Flea abundance was associated with host traits including sex and fecal glucocorticoid metabolite levels. The average number of fleas per individual and the proportion of individuals carrying fleas increased across years for T. speciosus but not for T. alpinus. To better understand these patterns, we constructed models to identify environmental predictors of flea abundance for the two most common flea species, Ceratophyllus ciliatus mononis and Eumolpianus eumolpi. Results showed host-dependent differences in environmental predictors of flea abundance for E. eumolpi and C. ciliatus mononis, with notable ties to ambient temperature variation and elevation. These results provide insight into factors affecting flea abundance on two chipmunk species, which may be linked to changing climate and possible future plague epizootics.

Efficacy of fluralaner spot-on solution for the treatment of Ctenocephalides felis and Otodectes cynotis mixed infestation in naturally infested cats

BackgroundCats can be infested with several ectoparasite species, especially Ctenocephalides felis and Otodectes cynotis. The aim of this study was to evaluate the efficacy of a single topical application of fluralaner against C. felis and O. cynotis natural infestation in stray (study 1) and owned (study 2) cats in central and southern Italy.ResultsThe number of live fleas found on each cat on Day 0 ranged from 1 to more than 30 (arithmetic mean live flea count = 11.9 in study 1; 14.6 in study 2) while no live fleas were found on days 7 and 84 post topical application of fluralaner. The number of live mites found on each cat on Day 0 ranged from 1 to 42 (arithmetic mean live mite count = 6.4 in study 1; 8.9 in study 2) while no live mites were found on days 7 and 84 post topical application of fluralaner.ConclusionsTopical fluralaner completely eliminated fleas and ear mites from infested cats and was 100% effective against both parasites up to 84 days after treatment.

The use of phoxim and bendiocarb for control of fleas in farmed mink (Mustela vison)

BackgroundFleas (Ceratophyllus sciurorum) are common on farmed mink in Denmark. When present, the fleas have a negative impact on the health of the farmed mink and are of nuisance for farm staff. Severe infestations of fleas cause anemia, poor growth and may result in death of mink kits. Changed behavior of the dams is also observed. Further it has been demonstrated that the fleas are vectors of Aleutian disease virus. Flea control is based on use of a few insecticides and resistance has been reported against permethrin. There is thus a need for new flea control products. In this blinded, randomized clinical trial according to GCP standard, phoxim spray and bendiocarb powder for flea control on mink farms were investigated.ResultsBoth the phoxim spray solution and bendiocarb powder were found to be efficient for the control of C. sciurorum fleas on farmed mink. Phoxim treatments reduced the number of fleas by 98.4% and the bendiocarb treatments reduced the number of fleas by 99.0% in the mink nest boxes when compared to counts in controls. No clinical signs were observed post treatment.ConclusionsThe study demonstrated that phoxim sprayed on the animals and the use of bendiocarb powder in the nest box material were highly efficient for the control of the C. sciurorum fleas on farmed mink. Both products were safe to use at the recommended dose rate. Both compounds are recommended to be integrated in a new farm management plan suggested here.

Parasitism of Black-Tailed Prairie Dogs by Linognathoides cynomyis (Phthiraptera: Polyplacidae).

The following study investigates louse parasitism of black-tailed prairie dogs (Cynomys ludovicianus (Ord, Rodentia: Sciuridae)) on 20 plots at 13 colonies in the short-grass prairie of New Mexico, USA, June-August, 2011-2012. Among 124 lice collected from 537 prairie dogs during 1,207 sampling events in which anesthetized animals were combed for ectoparasites, all of the lice were identified as Linognathoides cynomyis (Kim, Phthiraptera: Polyplacidae). Data were analyzed under an information-theoretic approach to identify factors predicting louse parasitism. Lice were most prevalent on plots with high densities of prairie dogs. At the scale of hosts, lice were most abundant on prairie dogs in poor body condition (with low mass:foot ratios) and prairie dogs harboring large numbers of fleas (Siphonaptera, mostly Oropsylla hirsuta (Baker, Siphonaptera: Ceratophyllidae) and Pulex simulans (Baker,Siphonaptera: Pulicidae)). Lice have been implicated as supplemental vectors of the primarily flea-borne bacterium Yersinia pestis (Yersin, Enterobacteriales: Yersiniaceae), a re-emerging pathogen that causes sylvatic plague in prairie dog populations. Coparasitism by lice and fleas, as found herein, might enhance plague transmission. L. cynomyis deserves attention in this context.