Flea Infestations

The relative importance of both environmental factors and host factors in explaining variation in prevalence and intensity of flea parasitism in small mammal communities is poorly established. We examine these relationships in an East African savanna landscape, considering multiple host levels: across individuals within a population, across populations within species, and across species within a landscape. We sampled fleas from 2672 small mammals of 27 species. This included a total of 8283 fleas, with 5 genera, and 13 species identified. Across individual hosts within a site, both rodent body mass and season affected total intensity of flea infestation, although the explanatory power of these factors was generally modest (<10%). Across host populations in a landscape we found consistently positive effects of host density and negative effects of vegetation cover on the intensity of flea infestation. Other factors explored (host diversity, annual rainfall, anthropogenic disturbance, and soil properties) tended to have lower and less consistent explanatory power. Across host species in the same landscape, we found that host body mass was strongly positively correlated with both prevalence and intensity of flea parasitism. The average robustness of a host species to disturbance was not correlated with flea parasitism. Cumulatively, these results provide insight into the complex roles of both intrinsic (host) and extrinsic (environmental) factors in explaining complex patterns of flea parasitism across a landscape.

Parasite success depends on both host profitability and the microenvironment provided by the host, which together define host-parasite compatibility and can differ between hosts. We experimentally disentangled the effects of host profitability and microenvironmental conditions provided by nest material on the reproduction of a nest-based ectoparasite when exploiting its main and an alternative avian host species. Parasite reproductive performance was similar on both hosts when breeding in nests of their own species, suggesting no difference in host-parasite compatibility between hosts. The apparent parasite specialization could therefore result from differences in host-parasite encounter processes. However, when hosts were successful, the main host produced more young in infested nests, whereas the alternative host produced less; furthermore, host reproductive performance was higher in nests of the main host species, suggesting that this nest material alleviates parasitism cost. Therefore, our results suggest different evolutionary responses to parasites of the main and alternative hosts, with either higher tolerance or higher resistance, modulated by nest material.

JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact [email protected]. abstract: In spatiotemporally varying environments, host-parasite coevolution may lead to either host or parasite local adaptation. Using reciprocal infestations over 11 pairs of plots, we tested local adaptation in the hen flea and its main host, the great tit. Flea reproductive success (number of adults at host fledging) was lower on host individuals from the same plot compared with foreign hosts (from another plot), revealing flea local maladaptation. Host reproductive success (number of fledged young) for nests infested by foreign fleas was lower compared with the reproductive success of controls, with an intermediate success for nests infested by local fleas. This suggests host local adaptation although the absence of local adaptation could not be excluded. However, fledglings were heavier and larger when reared with foreign fleas than when reared with local fleas, which could also indicate host local maladaptation if the fitness gain in offspring size offsets the potential cost in offspring number. Our results therefore challenge the traditional view that parasite local maladaptation is equivalent to host local adaptation. The differences in fledgling morphology between nests infested with local fleas and those with foreign fleas suggest that flea origin affects host resource allocation strategy between nestling growth and defense against parasites. Therefore, determining the mechanisms that underlie these local adaptation patterns requires the identification of the relevant fitness measures and life-history trade-offs in both species.

We studied the energy cost of egg production in two flea species (Parapulex chephrenis and Xenopsylla ramesis) feeding on principal (Acomys cahirinus and Meriones crassus, respectively) and auxiliary (M. crassus and A. cahirinus, respectively) rodent hosts. We predicted that fleas feeding on principal as compared with auxiliary hosts will (a) expend less energy for egg production; (b) produce larger eggs and (c) live longer after oviposition. Both fleas produced more eggs and spent less energy per egg when exploiting principal hosts. Parapulex chephrenis produced larger eggs after exploiting auxiliary hosts, while the opposite was true for X. ramesis. After oviposition, P. chephrenis fed on the auxiliary hosts survived for a shorter time than those fed on the principal hosts, while in X. ramesis the survival time did not differ among hosts. Our results suggested that one of the proximate causes for lower reproductive performance and subsequent lower abundance of fleas on auxiliary hosts is the higher energy cost of egg production. However, in some species, lower offspring number may be compensated to some extent by their size, although this compensation may also compromise their future reproduction via decreased survival. In addition, the reproductive strategy of exploitation of low profitable (i.e. auxiliary) hosts may differ between flea species.

Traditionally, efficient flea-borne transmission of Yersinia pestis, the causative agent of plague, was thought to be dependent on a process referred to as blockage in which biofilm-mediated growth of the bacteria physically blocks the flea gut, leading to the regurgitation of contaminated blood into the host. This process was previously shown to be temperature-regulated, with blockage failing at temperatures approaching 30°C; however, the abilities of fleas to transmit infections at different temperatures had not been adequately assessed. We infected colony-reared fleas of Xenopsylla cheopis with a wild type strain of Y. pestis and maintained them at 10, 23, 27, or 30°C. Naïve mice were exposed to groups of infected fleas beginning on day 7 post-infection (p.i.), and every 3-4 days thereafter until day 14 p.i. for fleas held at 10°C, or 28 days p.i. for fleas held at 23-30°C. Transmission was confirmed using Y. pestis-specific antigen or antibody detection assays on mouse tissues. ...

Host condition can influence both the nutritive resources available to parasites and the strength of host defences. Since these factors are likely to be correlated, it is unclear whether parasites would be more successful on hosts in good, intermediate or poor conditions. For more complex parasites, like fleas, where larvae depend on adults to extract and make available some essential host resources, host condition can act at two levels. First, it can affect the investment of females into eggs, and second, it can influence offspring growth. In a two-step experiment, we first let female hen fleas Ceratophyllus gallinae feed on nestlings of reduced, control or enlarged great tit Parus major broods and secondly used the blood from these nestlings as a food source for flea larvae reared in the laboratory. We then assessed the effect of brood size manipulation on reproductive investment and survival of female fleas, and on survival, developmental time, mass and size of pre-imago larvae and adults of the first generation. Although host condition, measured as body mass controlled for body size, was significantly influenced by brood size manipulation, it did not affect the female fleas' reproductive investment and survival. Larvae fed with blood from nestlings of reduced broods lived longer, however, than larvae fed on blood from enlarged or control broods. Additionally, F1 adults grew shorter tibiae when their mother had fed on hosts of reduced broods. The finding that brood size manipulation influenced parasite reproduction suggests that it affected nutritive resources and/or host defence, but the precise mechanism or balance between the two requires further investigation.

Due to a resurgence of flea-borne rickettsioses in Orange County, California, we investigated the etiologies of rickettsial infections of Ctenocephalides felis, the predominant fleas species obtained from opossums (Didelphis virginiana) and domestic cats (Felis catus), collected from case exposure sites and other areas in Orange County. In addition, we assessed the prevalence of IgG antibodies against spotted fever group (SFGR) and typhus group (TGR) rickettsiae in opossum sera. Of the 597 flea specimens collected from opossums and cats, 37.2% tested positive for Rickettsia. PCR and sequencing of rickettsial genes obtained from C. felis flea DNA preparations revealed the presence of R. typhi (1.3%), R. felis (28.0%) and R. felis-like organisms (7.5%). Sera from opossums contained TGR-specific (40.84%), but not SFGR-specific antibodies. The detection of R. felis and R. typhi in the C. felis fleas in Orange County highlights the potential risk for human infection with either of these ...

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.

Bartonella are emerging and re-emerging pathogens affecting humans and a wide variety of animals including rodents. Horizontal transmission of Bartonella species by different hematophagous vectors is well acknowledged but vertical transmission (from mother to offspring) is questionable and was never explored in fleas. The aim of this study was to investigate whether the rodent flea, Xenopsylla ramesis, can acquire native Bartonella from wild rodents and transmit it transovarially. For this aim, Bartonella-free laboratoryreared X. ramesis fleas were placed on six naturally Bartonella-infected rodents and six species-matched Bartonella-negative rodents (three Meriones crassus jirds, two Gerbillus nanus gerbils and one Gerbillus dasyurus gerbil) for 7 days, 12-14 h per day. The fleas that were placed on the Bartonella-positive rodents acquired four different Bartonella genotypes. Eggs and larvae laid and developed, respectively, by fleas from both rodent groups were collected daily for 7 days and molecularly screened for Bartonella. All eggs and larvae from both groups were found to be negative for Bartonella DNA. Interestingly, two of five gut voids regurgitated by Bartonella-positive fleas contained Bartonella DNA. The naturally infected rodents remained persistently infected with Bartonella for at least 89 days suggesting their capability to serve as competent reservoirs for Bartonella species. The findings in this study indicate that X. ramesis fleas can acquire several Bartonella strains from wild rodents but cannot transmit Bartonella transovarially.

Members of the order Rickettsiales are small, obligate intracellular bacteria that are vector-borne and can cause mild to fatal diseases in humans worldwide. There is little information on the zoonotic rickettsial pathogens that may be harboured by dogs from rural localities in South Africa. To characterize rickettsial pathogens infecting dogs we screened 141 blood samples, 103 ticks and 43 fleas collected from domestic dogs in Bushbuckridge Municipality, Mpumalanga Province of South Africa between October 2011 and May 2012 using the reverse line blot (RLB) and Rickettsia genus and species-specific qPCR assays. Results from RLB showed that 49% of blood samples and 30% of tick pools were positive for the genus-specific probes for Ehrlichia/Anaplasma; 16% of the blood samples were positive for Ehrlichia canis. Haemoparasite DNA could not be detected in 36% of blood samples and 30% of tick pools screened. Seven (70%) of tick pools and both flea pools were positive for Rickettsia spp; three (30%) of tick pools were positive for R. africae and both flea pools (100%) were positive for R. felis. Sequencing confirmed infection with R. africae and Candidatus Rickettsia asemboensis; a Rickettsia felis-like organism from one of the R. felis-positive flea pools. Anaplasma sp. South Africa dog strain (closely related to Anaplasma phagocytophilum), A. phagocytophilum, and an Orientia tsutsugamushi-like sequence were identified from blood samples. The detection of emerging zoonotic agents from domestic dogs and their ectoparasites in a rural community in South Africa highlights the potential risk of human infection that may occur with these pathogens.

Background: Tick-borne diseases comprise a group of maladies that are of substantial medical and veterinary significance. A range of tick-borne pathogens, including diverse species of bacteria and protozoa, can infect both dogs and humans. Hence, the control of tick infestations is pivotal to decrease or prevent tick-borne pathogen transmission. Therefore, different commercial products with insecticidal, repellent or both properties have been developed for use on dogs. Recently, a collar containing a combination of imidacloprid 10% and flumethrin 4.5% has proven effective to prevent tick and flea infestations in dogs under field conditions and the infection by some vector-borne pathogens they transmit under laboratory-controlled conditions.

Rickettsioses caused by Rickettsia felis are an emergent global threat. Historically, the northern region of the province of Caldas in Colombia has reported murine typhus cases, and recently, serological studies confirmed high seroprevalence for both R. felis and R. typhi. In the present study, fleas from seven municipalities were collected from dogs, cats, and mice. DNA was extracted and amplified by polymerase chain reaction (PCR) to identify gltA, ompB, and 17kD genes. Positive samples were sequenced to identify the species of Rickettsia. Of 1,341 fleas, Ctenocephalides felis was the most prevalent (76.7%). Positive PCR results in the three genes were evidenced in C. felis (minimum infection rates; 5.3%), C. canis (9.2%), and Pulex irritans (10.0%). Basic Local Alignment Search Tool (BLAST) analyses of sequences showed high identity values ( 98%) with R. felis, and all were highly related by phylogenetic analyses. This work shows the first detection of R. felis in fleas collected from animals in Colombia.

Fleas are important vectors of several Rickettsia and Bartonella spp. that cause emerging zoonotic diseases worldwide. In this study, 303 fleas collected from domestic dogs and cats in Ethiopia and identified morphologically as Ctenocephalides felis felis, C. canis, Pulex irritans, and Echidnophaga gallinacea were tested for Rickettsia and Bartonella DNA by using molecular methods. Rickettsia felis was detected in 21% of fleas, primarily C. felis, with a similar prevalence in fleas from dogs and cats. A larger proportion of flea-infested dogs (69%) than cats (37%) harbored at least one C. felis infected with R. felis. Rickettsia typhi was not detected. Bartonella henselae DNA was detected in 6% (2 of 34) of C. felis collected from cats. Our study highlights the likelihood of human exposure to R. felis, an emerging agent of spotted fever, and B. henselae, the agent of cat-scratch disease, in urban areas in Ethiopia.

Preclinical studies have shown that the novel isoxazoline, lotilaner (Credelio™, Elanco) administered orally to dogs, produces rapid flea and tick knockdown and sustained speed of kill for at least a month post-treatment with a wide safety margin. A field study was undertaken to validate pre-clinical results. Dogs were enrolled at 10 veterinary clinics across the United States. Qualifying households containing up to three dogs and one primary dog with at least 10 fleas were randomized 2:1 to receive lotilaner (Credelio™, Elanco) at the recommended minimum dose of 20 mg/kg, or afoxolaner (Nexgard®, Merial), administered per label, to give a minimum dose of 2.5 mg/kg. Treatments were dispensed on Days 0, 30 and 60 for administration by owners; all household dogs received the same treatment as the primary dog. Post-enrollment flea and tick counts were made on primary dogs on Days 30, 60 and 90, and all dogs were assessed for tablet palatability and safety. For efficacy assessments, dat...

Anthropogenic disturbance may lead to the spread of vector-borne diseases through effects on pathogens, vectors, and hosts. Identifying the type and extent of vector response to habitat change will enable better and more accurate management strategies for anthropogenic disease spread. We compiled and analyzed data from published empirical studies to test for patterns among flea and small mammal diversity, abundance, several measures of flea infestation, and host specificity in 70 small mammal communities of five biomes and three levels of human disturbance: remote/wild areas, agricultural areas, and urban areas. Ten of 12 mammal and flea characteristics showed a significant effect of disturbance category (six), biome (four), or both (two). Six variables had a significant interaction effect. For mammal-flea communities in forest habitats (39 of the 70 communities), disturbance affected all 12 characteristics. Overall, flea and mammal richness were higher in remote versus urban sites. Most measures of flea infestation, including percent of infested mammals and fleas/mammal and fleas/mammal species increased with increasing disturbance or peaked at intermediate levels of disturbance. In addition, host use increased, and the number of specialist fleas decreased, as human disturbance increased. Of the three most common biomes (forest, grassland/savanna, desert), deserts were most sensitive to disturbance. Finally, sites of intermediate disturbance were most diverse and exhibited characteristics associated with increased disease spread. Anthropogenic disturbance was associated with conditions conducive to increased transmission of flea-borne diseases.

A cross-sectional study was conducted in the Eastern part of Zambia that previously reported a plague outbreak. The aim of the study was to evaluate the potential role of pigs, goats, and sheep as sero-surveillance hosts for monitoring plague, and to investigate the flea vectors and potential reservoir hosts to establish the current status of plague endemicity in the district. Serum samples were collected from 96 rodents, 10 shrews, 245 domestic pigs, 232 goats, and 31 sheep, whereas 106 organs were eviscerated from rodents and shrews. As for fleas, 1,064 Echidnophaga larina Jordan & Rothschild, 7 Xenopsylla cheopis (Rothschild), and 382 Echidnophaga gallinacea (Westwood) were collected from these animals in 34 villages. Enzyme-Linked Immunosorbent Assay (ELISA) and Polymerase Chain Reaction (PCR) tests were performed on serum, and organs and fleas to determine IgG antibodies against Fraction 1 antigen and pla gene of Yersinia pestis, respectively. ELISA results showed that 2.83% (9...

This study was conducted to evaluate the efficacy of a new topical ectoparasiticidal spot-on containing 4.95 % dinotefuran (w /w), 36.08 % permethrin (w/w) and 0.44 % pyriproxyfen (w/w)( V e c t r a3 D ™, Ceva, Libourne, France) against Portuguese strain of Phlebotomus perniciosus and a French strain of Ctenocephalides canis in dogs. Twelve beagle dogs were exposed for 1 h to 100 P. perniciosus on day 6 for allocation in two groups. One group was treated on day 0, and the other group was the control group. The dogs were exposed for 1 h to 100 P. perniciosus on days 1, 7, 14, 21 and 28. After each sandfly challenge, the same dogs were infested with 100 C . canis. Counts of living fleas were determined 48 h after infestation on days 4, 3, 9, 16, 23 and 30. For sandflies, the anti-feeding effect was 96.9, 99.7, 98.7, 83.5 and 87.0 % on days 1, 7, 14, 21 and 28, respectively. The mortality effect was 97.8, 99.8, 73.7, 27.5 and 39.6 % on days 1, 7, 14, 21 and 28, respectively. At each challenge point, the mortality and anti-feeding effects on sandflies were significantly different between the control and treatment groups (p <0.05). The adulticidal effect on C . canis remained above 99 % throughout the study period. The results indicate that a combination with dinotefuran, permethrin and pyriproxyfen may be used as an effective part of an overall flea and sandfly control strategy in dogs for monthly use.

This study investigated the efficacy of two collars for the treatment and prevention of flea infestations. Additionally the effect of these collars on the incidence of Leishmania infantum infection as compared with a group of vaccinated dogs was evaluated. A total of 224 young dogs from private animal shelters were enrolled in April/May into four groups: G1, 55 dogs treated with 10% imidacloprid + 4.5% flumethrin collar (Seresto, Bayer Animal Health); G2, 60 dogs treated with 4% deltamethrin collar (Scalibor protector band, MSD Animal Health); G3, 54 dogs vaccinated with CaniLeish (Virbac Animal Health); and G4, 55 dogs left non-treated as controls. Dogs were followed up at days 120 (September), 210 (December), and 360 (April-May). At those time points, clinical assessments, ectoparasite counts and blood, bone marrow and skin samples, to detect the presence of L. infantum, were performed. The efficacy of Seresto in protecting dogs from flea infestation was 100% (P < 0.01) on day 120 and 210, while animals treated with Scalibor showed a prevalence of the infestation ranging from 23.3% to 33.3% on day 120 and 210, respectively. At the end of the study, the incidence of L. infantum infection in collared dogs-based on animals being positive in any of the tests-was 5.5% in Seresto-treated dogs and 20% in Scalibor-treated dogs, resulting in overall efficacy of prevention of 88.3% for Seresto and 61.8% for Scalibor. No statistical difference was detected in L. infantum positive dogs for bone marrow PCR and/or cytology at day 360 between the CaniLeish (15.4%) and non-treated control dogs (10.0%). Both collars proved to be effective (P < 0.01) in preventing L. infantum infection throughout one transmission season, whereas no significant difference was recorded in the frequency of active infections between dogs vaccinated with CaniLeish and control dogs, emphasizing the importance of using repellent/ insecticide actives as a priority measure for protection against canine leishmaniosis.

Tungiasis is caused by infestation with the sand flea (Tunga penetrans). This ectoparasitosis is endemic in economically depressed communities in South American and African countries. However, data on the epidemiology of tungiasis in Tanzania are very limited and the disease does not receive much attention from health care professionals. During a community cross sectional survey in northwest Tanzania, we identified five individuals extremely infested with high number of parasites. A total of 435 lesions were recorded with patients presenting with >75 lesions and showed signs of intense acute and chronic inflammation. Superinfection of the lesions characterized by pustule formation, suppuration and ulceration were common. Loss of nails and walking difficulty was also observed. In Tanzanian communities living under extreme poverty characterized by poor housing condition and inadequate health services, tungiasis may cause severe morbidities. Further studies on risk factors and disease-related behavior of affected populations are needed to design adequate control measures. This work is licensed under a Creative Commons Attribution 3.0 License (by-nc 3.0). ©Copyright H.D.

Herpestes auropunctatus, the small Indian mongoose, is an invasive omnivore introduced to the Caribbean, including the island of St. Kitts over 150 years ago. It has played a role in changing native fauna and can carry zoonotic pathogens of public health importance. The aim of the current study was to estimate the prevalence of parasites harbored by mongooses. In total, 87 mongooses trapped from April to July 2015 were examined for parasites using (1) hair plucks (N = 79), ear swabs (N = 79), and general coat and skin examination (N = 87) for mites, ticks, lice, and fleas; (2) dissection of the trachea, bronchi, and lungs for lungworms and flukes (N = 76); (3) a double centrifugation fecal flotation method for parasites of the gastrointestinal tract (N = 75); and (4) PCR of heart homogenates for Toxoplasma gondii (N = 60). The only ectoparasite seen was Ctenocephalides felis (79.3%; 69/87), with most mongooses having &gt; 10 fleas (based on a subjective assessment) but insufficient ...

Background: Bartonella henselae is transmitted amongst cats by Ctenocephalides felis and is associated with multiple clinical syndromes in cats and people. In a previous study, monthly spot-on administration of 10% imidacloprid/1% moxidectin was shown to block transmission of B. henselae amongst cats experimentally exposed to infected C. felis. The purpose of this study was to determine whether application of a flea and tick collar containing 10% imidacloprid and 4.5% flumethrin would lessen C. felis transmission of B. henselae amongst cats for 8 months. Methods: Specific pathogen free cats (n = 19) were housed in three adjoining enclosures that were separated by mesh to allow C. felis to pass among groups but prevent cats in different enclosures from contacting one another. One group of 4 cats was inoculated intravenously with B. henselae and after infection was confirmed in all cats based on positive PCR assay results, the cats were housed in the middle enclosure. The B. henselae infected cat group was flanked by a group of 8 cats that had the collar placed and maintained for the duration of the study and a group of 7 cats that were not treated. Ctenocephalides felis (50 males and 50 females) raised in an insectary were placed on each of the 4 cats in the B. henselae infected group monthly for 7 applications and then every 2 weeks for 4 applications starting the day the collar was applied. Blood was collected from all cats weekly for Bartonella spp. PCR, serology and culture.

The association between the prevalence of infestation by Rhipicephalus sanguineus and Ctenocephalides felis felis and the presence of anti-Leishmania antibodies has been evaluated in dogs located in a city of Brazil endemic for canine visceral leishmaniasis. Blood samples from 5556 domestic dogs domiciliated in the urban area of Belo Horizonte (Minas Gerais state) were submitted to enzyme linked immunosorbent (ELISA) and indirect immunofluorescent antibody (IFAT) assays, and 432 (7.8%) animals tested positive. Seropositive (n = 200) and seronegative (n = 200) dogs were randomly selected and examined for the presence of ticks and fleas, the results of which were expressed qualitatively as infested or non-infested, irrespective of the intensity of infestation. The prevalence of infestation by R. sanguineus was significantly greater ( = 0.04) among seropositive dogs (38.5%) compared with their seronegative counterparts (29.0%). Similarly, the prevalence of infestation by C. felis felis was significantly greater ( < 0.01) within the seropositive group (36.5%) than within the seronegative group (15.0%). Moreover, the probability of seropositivity for Leishmania was 53% higher in tick-infested dogs and 300% higher in flea-infested dogs in comparison with non-infested animals. Our data provide evidence of the vectorial capacity of these ectoparasites in transmitting Leishmania to the canine population, although further studies are needed to confirm or reject this hypothesis.

Lotilaner is a novel isoxazoline developed for oral administration to dogs. In laboratory studies, lotilaner was shown to be safe and to produce a rapid flea and tick knockdown, with a sustained speed of kill for at least a month post-treatment. A study was undertaken to demonstrate the efficacy, safety and palatability of three monthly doses of lotilaner flavoured chewable tablets (Credelio™, Elanco) in controlling fleas under field conditions in Europe. Dogs were enrolled at 17 veterinary clinics across Germany, Hungary and Portugal. Qualifying households having no more than three dogs and one primary dog with at least five fleas was randomised 2:1 to a lotilaner (minimum dose rate 20 mg/kg) or a topical fipronil group (administered per label). There were 128 and 64 households allocated to the lotilaner and fipronil groups, respectively. Treatments were dispensed to owners on Days 0, 28 and 56; supplementary household dogs received the same treatment as the primary dog. Post-enrol...

he eicacy of rodent bait containing the insecticide imidacloprid was evaluated for controlling leas on the California ground squirrel, Spermophilus beecheyi. he bait was designed to deliver an oral dose of insecticide resulting in lea mortality when obtaining a blood meal. During the ive-week trial, performed at Vandenberg Air Force Base, Santa Barbara County, CA, a spot-baiting technique was used to apply bait to ground squirrel burrows. Bait was applied six times throughout the trial. Results indicated that the use of a host-targeted bait was efective in signiicantly reducing the lea burden on S. beecheyi. Eicacy at reducing lea abundance was near 100% at both day 15 and day 29 of the trial. Use of the bait also reduced the prevalence of lea-infested S. beecheyi. Our results indicate that the use of rodent bait containing insecticide could provide an efective, economical method of controlling the leas of S. beecheyi, the primary vectors of human plague in California. Journal of Vector Ecology 34 (1): 92-98. 2009.

Lotilaner (Credelio™) is the newest member of the novel isoxazoline chemical class to be developed to treat canine ectoparasitism. Administered orally, lotilaner is rapidly absorbed with peak blood levels occurring within 2 h post-treatment. A study was undertaken to determine the earliest onset of lotilaner&#39;s efficacy against existing flea infestations. From 72 Beagles, 64 qualifying dogs were ranked in descending order of flea counts from a Day -8 infestation and placed into eight blocks. Within blocks, eight dogs were randomly allocated among eight groups: Groups 1 to 4 were treated orally with lotilaner, at as close as possible to the minimum dose rate of 20 mg/kg within 30 (± 5) minutes after feeding; Groups 5 to 8 were untreated controls. All dogs were infested with 100 ± 5 fleas on Day -2, and whole-body flea counts were completed at 30 min and one, two and 8 h after treatment. Efficacy calculations were based on arithmetic and geometric means if an adequate infestation (...

Four studies were conducted to examine the efficacy of a novel topical combination of fipronil, (S)-methoprene, eprinomectin, and praziquantel (BROADLINE ® , Merial) against Ancylostoma tubaeforme and Ancylostoma braziliense hookworms of cats. In each study, purpose-bred cats were randomly assigned to treatment groups of 10 or 12 cats per group. In three studies the cats were inoculated with A. tubaeforme and in one study with A. braziliense. The inoculations were undertaken on a schedule which resulted in the hookworms reaching the fourth larval stage in two of the studies, or the adult stage in four of the studies, by the day of treatment. In each study there was also an untreated control and 1 or 2 groups treated with the novel combination. In the two studies where efficacy against the fourth larval stage of A. tubaeforme was tested, the efficacy recorded was 100%. In the three studies where efficacy against the adult stage of A. tubaeforme was tested, efficacy of 100% was also confirmed. In the study where efficacy against the adult stage of A. braziliense was tested efficacy was 99.5%.

Lotilaner (Credelio™, Elanco), a novel isoxazoline, is a systemic insecticide and acaricide that is rapidly absorbed following oral administration to dogs and has a half-life of 30 days. As part of a development program, studies were undertaken to investigate lotilaner&#39;s initial and sustained efficacy and speed of kill against fleas. Four studies were conducted to evaluate the onset of lotilaner&#39;s speed of flea knockdown at the time of treatment, and to determine the sustained speed of flea kill (SOK) up to 35 days post-treatment. Each study assessed one or two specific time points (4, 6, 8 and 12 h) post-treatment and following weekly re-infestations. In each study, dogs were randomised to a lotilaner or an untreated group based on pre-administration flea counts, and before treatment were infested with adult Ctenocephalides felis. Dogs randomised to a lotilaner group received a single treatment on Day 0, at the minimum recommended dose rate of 20 mg/kg, 30 (± 5) minutes aft...

In the study reported here, the pioneer fipronil/(S)-methoprene topical product (FRONTLINE ® PLUS, Merial Limited, Duluth, GA) was compared to the oral spinosad product (COMFORTIS ® Elanco, Greenfield, IN) for efficacy against adult fleas and preventing egg production. The product presentations, doses and labelling were the one applicable in the USA. Using a standard protocol, 200 cat fleas of mixed sex were applied to dogs on Days 1, 7, 14, 21, 28, 35, and 42. Dogs were combed to remove fleas 24 hours post-infestation, the fleas were counted, collected, and then reapplied to each dog following completion of their respective count. At 48 hours post-infestation, comb counts were performed and fleas were removed. No fleas were collected from any dog in the fipronil/(S)-methoprene group at any 24 or 48 hours postinfestation assessment throughout the six weeks study, yielding a preventive efficacy of 100 %. For the spinosad treatment, efficacy was 100 % at 24 hours and 48 hours through Day 16, and thereafter declined. The results observed in the spinosad-treated dogs were highly variable between animals. At the 24 and 48 hours counts following the Day 21 infestation, only five of eight spinosad-treated dogs (62.5 %) were flea-free. Following the Day 28 infestation, spinosad efficacy fell to 85 % and 89 %, for the 24 hours and 48 hours counts, and only two dogs (25 %) were flea free, compared to 100 % flea-free dogs in the fipronil/(S)methoprene group. No fleas were collected from the fipronil/(S)methoprene treated dogs throughout the entire study, therefore, no eggs were collected at any time from any dog in the group. However, in the spinosad group adult fleas were found on dogs starting on Day 21 and by Day 30, 42 eggs were collected from one dog that had 107 adult fleas counted at 48 hours. At Day 37 and Day 49, more than 100 eggs were collected from each dog in the spinosad-treated and control groups. KEY WORDS: fipronil/(S)-methoprene, spinosad, Ctenocephalides felis felis, duration of efficacy, flea egg, FRONTLINE ® PLUS, COMFORTIS ® . Résumé : COMPARAISON DE L'EFFICACITÉ DU TOPIQUE À BASE DE FIPRONIL/(S)-MÉTHOPRÈNE À CELLE DU TRAITEMENT ORAL PAR SPINOSAD CONTRE CTENOCEPHALIDES FELIS CHEZ LE CHIEN Dans l'étude ici présentée, le produit topique princeps à base de fipronil/(S)méthoprène (FRONTLINE ® PLUS, Merial Limited, Duluth, GA) 0, 7, 14, 21, 28, 35 et 42

Background: Two studies were conducted to evaluate and compare the efficacy of imidacloprid + moxidectin and selamectin topical solutions against the KS1 flea strain infesting cats. In both studies the treatment groups were comprised of non-treated controls, 6% w/v selamectin (Revolution ® ; Pfizer Animal Health) topical solution and 10% w/v imidacloprid + 1% w/v moxidectin (Advantage Multi ® for Cats, Bayer Animal Health) topical solution. All cats were infested with 100 fleas on Days -2, 7, 14, 21, and 28. The difference in the studies was that in study #1 efficacy evaluations were conducted at 24 and 48 hours post-treatment or post-infestation, and in study #2 evaluations were conducted at 12 and 24 hours.

Background: The objective of the study was to determine the sustained effectiveness of 10% imidacloprid (w/w) and 4.5% flumethrin (w/w) incorporated in a slow-release matrix collar in preventing Dipylidium caninum infection in cats following repeated laboratory-infestations with fleas infected with metacestodes. Methods: Efficacy against infection with D. caninum was evaluated by infesting 16 cats with the flea Ctenocephalides felis felis infected with metacestodes of the tapeworm. Medicated collars were fitted to 8 of the cats and infestation of each cat with 200 fleas from a suitably infected batch commenced 7 days later and continued at weekly intervals until Day 28. Efficacy against fleas was evaluated 24 h after each infestation. Infection of the cats with D. caninum was verified by daily examination of the cats' faeces and immediate surroundings for proglottids from Day 21 to Day 60. Calculation of the prophylactic effectiveness of the collars in preventing infection of the cats with D. caninum was based on the difference in the geometric mean number of scoleces recovered from the gastrointestinal tracts of collared compared to untreated cats at necropsy on Day 61. Results: Efficacy of the collars against infestation of the cats with fleas was 99.9% on Day 7 and 100% at each subsequent weekly assessment. Infection of the fleas with metacestodes was ≥40% in 7 to 13 day old fleas, but progressively decreased thereafter. At necropsy all the control cats were infected with D. caninum and harboured between 19 and 346 scoleces with a geometric mean of 58.3. A single treated cat was infected and harboured 2 scoleces. Effective prevention of infection with D. caninum, based on a comparison of the geometric mean numbers of scoleces recovered from control and treated cats, was 99.7%. Conclusion: The insecticidal components of the medicated collars are capable of rapidly eliminating newlyacquired infestations of fleas that are infected with the metacestodes of D. caninum, thus preventing infection with the cestode in collared cats.

Background: Precise data on quantitative kinetics of blood feeding of fleas, particularly immediately after contact with the host, are essential for understanding dynamics of flea-borne disease transmission and for evaluating flea control strategies. Standard methods used are inadequate for studies that simulate early events after real-life flea access to the host. Methods: Here, we developed a novel quantitative polymerase chain reaction targeting mammalian DNA within fleas to quantify blood consumption with high sensitivity and specificity. We used primers and fluorescent probes that amplify the hydroxymethylbilane synthase (HMBS) gene, an evolutionary divergent gene that is unlikely to be detected in insects by mammalian-specific primers and probes. To validate this assay, fleas were placed on dogs, allowed to distribute in the hair, and removed at specific time points with single-use combs. Fleas were then immediately homogenized by vigorous shaking with ceramic beads in guanidinium-based DNA preservation buffer for DNA extraction. Results: The specificity of this assay was ascertained by amplification of canine, feline and equine blood with differential product melting temperatures (T m ), and lack of amplification of bovine and porcine blood and of adult fleas reared from larvae fed with bovine blood. Sensitivity of the assay was established by limiting dilution and detection of single copies of HMBS DNA equivalent to 0.043 nL blood. Application of the assay indicated that after 15 minutes on a dog, male and female fleas had ingested low, but similar amounts of approximately 1.1. nL blood. Saturation uptake of 118 and 100 nL blood per flea was found at 30 and 60 min on the dog, respectively. Conclusions: The HMBS PCR method developed here offers the advantages of both exquisite sensitivity and specificity that make it superior to other approaches for quantification of blood ingested by fleas. The capability to detect minute quantities of blood in single fleas, particularly immediately after colonization of the host, will provide a superior tool for studying flea-host interactions, flea-borne disease transmission, and flea control strategies.

At Valles Caldera National Preserve in New Mexico, USA, infusing Gunnison&#39;s prairie dog ( Cynomys gunnisoni) burrows with an insecticide dust containing 0.05% deltamethrin killed fleas which transmit bubonic plague. The reduction in the number of fleas per prairie dog was significant and dramatic immediately after infusions, with a suggestion that the reduction persisted for as long as 12 mo. Despite the lower flea counts, however, a plague epizootic killed &gt;95% of prairie dogs after 3 yr of infusions (once per year). More research is necessary for a better understanding of the efficacy of insecticide dusts at lowering flea counts and protecting prairie dogs from plague.

The introduction of an exotic species usually modifies parasite-host dynamics by the import of new parasites or the exotic species' acquiral of local parasites. The loss of parasites may determine the outcome of an invasion if the introduced species is liberated from co-evolved parasites in its range of invasion. In addition, an introduced species may pose sanitary risks to humans and other mammals if it serves as a reservoir of pathogens or carries arthropod vectors. The redbellied squirrel, Callosciurus erythraeus (Pallas) (Rodentia: Sciuridae), was introduced into Argentina in 1970, since when several foci of invasion have been closely associated with humans. Investigation of the parasitological fauna of C. erythraeus in Argentina will generate new information about novel parasite-host dynamics and may provide new insight into the reasons for the successful invasion of this species. The objective of this study was to describe the arthropod parasites of C. erythraeus in Argentina in comparison with previous studies of parasites of this species in its native habitat and in the ranges of its invasion. Occasional host-parasite associations with local arthropod parasites not previously described for C. erythraeus are reported; these include the mites Androlaelaps fahrenholzi (Ewing) (Mesostigmata: Laelapidae) and Ornithonyssus cf. bacoti (Mesostigmata: Macronyssidae), the flea Polygenis (Polygenis) rimatus Jordan (Siphonaptera: Rhopalopsyllidae) and the botfly Cuterebra Clark (Diptera: Oestridae: Cuterebrinae). Cheyletus sp. mites (Trombidiformes: Cheyletidae) were also found. The low prevalence and mean intensity of ectoparasite species may influence invasion dynamics.

In 2001, an international surveillance initiative was established, utilising a validated larval development inhibition assay to track the susceptibility of cat flea isolates to imidacloprid. In 2009, an Australian node was incorporated into the programme, joining laboratories in the United States and Europe. Field isolates of Ctenocephalides felis eggs were submitted to participating laboratories and, where egg quantity and quality was sufficient, were placed in the imidacloprid discriminating dose bioassay for evaluation. Between 2002 and 2012, a total of 2,307 cat flea isolates were received across all sites; 1,685 submissions (73 %) were suitable for placement into the bioassay. In the Northern Hemisphere, isolate submission rate was influenced by season, with highest numbers submitted S48 ECTOPAR ASITES between June and October. In Australia, pets with flea infestations could be sourced yearround, and submission rate was largely influenced by programme factors and not climate. A total of 1,367 valid assays were performed between 2002 and 2012 (assay validity data was not recorded in 2001); adult flea emergence 5 % or greater at 3 ppm imidacloprid was observed in 38 of these assays (2.8 %). For these isolates that reached the threshold for further investigation, re-conduct of the assay using either a repeat challenge dose of 3 ppm of imidacloprid or a dose response probit analysis confirmed their susceptibility to imidacloprid. From 2009 to 2012, the Australian node performed valid assays on 97 field isolates from a total of 136 submissions, with no adult emergence observed at the 3-ppm imidacloprid discriminating dose. In addition to reviewing the data generated by this twelve-year initiative, this paper discusses lessons learned from the coordination and evolution of a complex project across geographically dispersed laboratories on three continents.

A new public health problem arises from animal trypanosomes that afflict human by a disease called atypical human trypanosomiasis. Although humans have an innate protection against most Trypanosoma species, nineteen cases of atypical human trypanosomiasis caused by the animal trypanosome as T. b. brucei , T. vivax, T. congolense , T. evansi and T. lewisi have been recorded. Some of theserecorded cases were transient, six required trypanocidal treatments however two patients died. Rodent trypanosome, T.lewisi is transmitted via ingestion of fleas or their feces containing the infective stage, the metacyclic trypomastigote. Because of the high densities of various species of rodents and their distribution all over the country especially in rural areas, the present work aimed to evaluate the trypanosomiasis among rodents collected from November to March 2016 and study transmission probability by their fleas in some rural areas in Abu Alnomros Center, Giza. The overall trypanosomiasis prevalence among the different rodent species was (21 rats) 24.7%. All the infected rats belonged to Rattus r. spp where the prevalence of infection with Trypanosoma lewisi among that species was very high 51.2% while none of rats belonged to Rattus norvegicus were infected. That may be attributed to the solid immunity gained by the R. norvegicus where most of the collected norvegicus were aged and weighed more than 200 grams. There was an inverse significant correlation between the densities of parasites and the weights of the hosts. The rat which recorded the highest parasite density (60,000 parasites/ microliter) was a female Rattus r. captured indoor (inside house). As to sex of Rattus rattus spp no significant difference was found between males and females in trypanosomiasis. Also there was no significant correlation between the densities of parasites and the number of white blood cells among Rattus rattus spp. All positive rats were collected indoors (from houses) and all the rats which were captured from outdoors (farms) were negative for T. lewisi. The difference between infections with trypanosomiasis among rats inhabited the houses and that found in farms was highly significant. Only two species of fleas were found on rats, Xenopsylla cheopis and Leptopsylla segnis. The oriental fleas, X. cheopis, were found mainly on R. norvegicus where 57.5% of R. norvegicus were positive for X. cheopis while only one rat was positive for L. segnis. On other hand the rat fleas, L.segnis, were found mainly on Rattus rattus spp where 39% of these rats were positive for L. segnis. The present work revealed a significant correlation between the infection with T. lewisi and the presence of L. segnis on the rats however that correlation regarding X. cheopis was not significant.