Flea-associated zoonotic diseases of cats in the USA: bartonellosis, flea-borne rickettsioses, and plague

Effects of blood meal source on blood consumption and reproductive success of cat fleas, Ctenocephalides felis

Cat fleas, small blood-feeding ectoparasites that feed on humans and animals, cause discomfort through their bites, and can transmit numerous diseases to animals and humans. Traditionally, fleas have been reared for research on live animals, but this process requires animal handling permits, inflicts discomfort on animals, and requires money and time to maintain the host animals. Although artificial membrane-based feeding systems have been implemented, these methods are not sustainable in the long term because they result in lower blood consumption and egg production than those with rearing on live hosts. To maximize these parameters, we tested blood from four hosts to determine the most suitable blood, on the basis of blood consumption and egg production. We also tested the effects of adding the phagostimulant adenosine-5´-triphosphate to the blood to maximize blood consumption. In 48 hours, fleas fed dog blood consumed the most blood, averaging 9.5 μL per flea, whereas fleas fed on cow, cat, or human blood consumed 8.3 μL, 5.7 μL, or 5.2 μL, respectively. Addition of 0.01 M and 0.1 M adenosine-5´-triphosphate to dog and cow blood did not enhance blood consumption. In a 1-week feeding period, the total egg production was also greatest in fleas fed dog blood, with females producing 129.5 eggs, whereas females on cat, human, and cow blood produced 97.2, 83.0, and 70.7 eggs, respectively. The observed results in dog blood indicate an improvement over previously reported results in cat fleas fed with an artificial feeding system. Improving the sustainability of rearing cat flea colonies without feeding on live animals will enable more humane and convenient production of this pest for scientific research.

Zoonotic Risks of Sleeping with Pets

Background: Pets are increasingly becoming part of the family and interactions between pets and their owners is changing. This results in extended and more intimate contact between owners and their pets, which give rise to zoonotic risks. Objective: To establish the presence of potential zoonotic pathogens in pets that sleep with their owner. Methods: As a pilot study, a group of 28 healthy dogs and 22 healthy cats were monitored for the presence of the zoonotic parasites Cheyletiella, Ctenocephalides spp. and Toxocara spp., the dermatophyte Microsporum canis, and the bacteria Clostridium difficile, Salmonella spp., Campylobacter jejuni and Enterobacteriaceae. This was investigated by taking samples from the fur, the footpads and the animal bed. The owners filled in a questionnaire. Results: In total, 29 of the 50 pets (58%) slept on the bed, of which 15 pets (30%) slept in the bed (under the blankets). A total of 19/22 dogs (86%) and 7/22 cats (32%) tested positive for Enterobacteriaceae on the fur or footpads. Fleas were found in 5/22 of the cats’ (23%) and 2/28 of the dogs’ (7%) favourite sleeping spots. High levels of aerobic colonies were found, up to 216 colony forming units/cm². Other pathogens were not found in this study. Conclusions: The results of this preliminary study confirm literature reports that pets may constitute a potential risk in the transmission of zoonotic pathogens to their owner, especially during direct contact when sleeping in the same bed. Owners should therefore be informed about these risks and educated to interact with their pets in a more responsible way.

Cat Owners' Perceptions toward Flea Infestation and Flea-borne Diseases: Impact for Public Health and Community Awareness

A structured questionnaire was distributed to a total of 531 cat owners in Peninsular Malaysia to evaluate their perceptions toward fleas and flea-borne diseases (FBD) using a knowledge-attitude-practice (KAP) approach. This study showed that majority of cat owners (50.5%) had a moderate level of knowledge on fleas, while 65.3% of them had a relatively low level of knowledge on FBD. However, most of them had positive attitudes (87.9%) and good practices (94.5%) toward efforts on prevention from flea infestation and FBD. Statistical analysis showed significant associations between knowledge on fleas and FBD toward demographic and pet ownership profiles of the respondents. Educated cat owners from urban area were more likely to have positive attitudes toward prevention of fleas and FBD. Female cat owners with monthly income of RM 5,001-7,000 ($1143-1600) were more likely to have good practices. Middle-aged cat owners showed the highest odds toward both positive attitudes and good practices. Correlation analyses indicated significant linear relationships between both knowledge, which were also associated with attitudes, but not with practices.

MORPHOLOGICAL AND MOLECULAR CHARACTERIZATION OF THE PLAGUE VECTOR XENOPSYLLA BRASILIENSIS

Members of the flea family Pulicidae have been the focus of many studies due to their significance as diseases vectors of medical and veterinary importance and their cosmopolitan distribution. They often exhibit variation in morphological features that can make correct species identification and management challenging. This may also apply to Xenopsylla brasiliensis (Baker, 1904), an important plague vector. In the current study, we aimed to provide genetic tools for reliable species identification using a DNA barcoding approach. A total of 73 flea specimens was collected from a native host (Namaqua rock mouse, Micaelamys namaquensis) in South Africa and identified morphologically. In addition, we took measurements of 7 morphological characteristics. Subsequently, we successfully generated barcodes of the mitochondrial cytochrome c oxidase subunit I (COI) gene for X. brasiliensis. We validated this approach by comparing our data to COI sequences from Rwandan X. brasiliensis. While sequences from both regions suggested a close relationship between the 2 X. brasiliensis populations, both haplotype and nucleotide diversity were substantially larger for the South African specimens. This may be attributed to human-assisted spread, differences in habitat, and/or host species sampled and merits further study in the future.

Analysis of gaps in feline ectoparasiticide purchases from veterinary clinics in the United States

Background

The study objective was to examine cat owner ectoparasiticide purchases in the United States and estimate the impact of purchase gaps on timely ectoparasite protection administration. These purchase gaps lead to periods of time when cats are unprotected from ectoparasites.

Methods

Ectoparasiticide purchase transactions for individual cats from 671 U.S. veterinary clinics from January 1, 2017 through June 30, 2019 were evaluated to determine time “gaps” between doses of ectoparasiticides purchased in a defined 12-month period. Ectoparasiticides examined were topically applied products that contained fluralaner, fipronil/(S)-methoprene/pyriproxyfen, imidacloprid/pyriproxyfen or selamectin as active ingredients. The duration of protection following administration of one dose was 8–12 weeks for the fluralaner-containing product and one month for the other products.

Results

Ectoparasiticide purchase records were obtained from 114,853 cat owners and analysis found that most owners bought ≤ 6 months of protection during the year, with 61–75% (depending on the product) purchasing just 1–3 months of protection. The size of the average purchase gap was determined for all dose combinations out to 12 months of protection (5–7 doses for fluralaner and 12 doses for the other three products dosed monthly. The largest gaps occurred between the first and second doses and the second and third doses. Average purchase gaps for the four different products between doses 1 and 2 ranged from 11.2 to 13.9 weeks and between doses 2 and 3 ranged from 7.7 to 12.2 weeks. The fraction of purchases separated by gaps and the average length of the gap tended to decrease with increasing number of doses purchased. Owners purchasing the 8 to 12-week duration product containing fluralaner provided ectoparasite protection (“doses plus gap period”) for a larger proportion of each 2-dose period compared with owners purchasing products administered monthly.

Conclusions

When cat owners purchase flea and tick medication, gaps between subsequent purchases reduces the proportion of time ectoparasite protection can be provided. The duration of the gap between doses has an impact on the effectiveness of flea/tick medication because it inserts a period without flea and tick protection between doses of flea and tick medication. The gaps between purchases were shorter and the period of ectoparasite protection was larger for owners purchasing a 12-week product than for owners purchasing a monthly product.

Arthropod Ectoparasites Have Potential to Bind SARS-CoV-2 via ACE

Coronavirus-like organisms have been previously identified in Arthropod ectoparasites (such as ticks and unfed cat flea). Yet, the question regarding the possible role of these arthropods as SARS-CoV-2 passive/biological transmission vectors is still poorly explored. In this study, we performed in silico structural and binding energy calculations to assess the risks associated with possible ectoparasite transmission. We found sufficient similarity between ectoparasite ACE and human ACE2 protein sequences to build good quality 3D-models of the SARS-CoV-2 Spike:ACE complex to assess the impacts of ectoparasite mutations on complex stability. For several species (e.g., water flea, deer tick, body louse), our analyses showed no significant destabilisation of the SARS-CoV-2 Spike:ACE complex, suggesting these species would bind the viral Spike protein. Our structural analyses also provide structural rationale for interactions between the viral Spike and the ectoparasite ACE proteins. Although we do not have experimental evidence of infection in these ectoparasites, the predicted stability of the complex suggests this is possible, raising concerns of a possible role in passive transmission of the virus to their human hosts.

What Is in a Cat Scratch? Growth of Bartonella henselae in a Biofilm

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.

Ovicidal action of insectoacaricide drugs sentry home, Neostomazan 1:200 manufacured by CEVA, Neostomazan 1:200 manufacured by product and Extrazol M on fleas Ctenocephalides spp. eggs

The aim of the research. To compare the ovicidal efficiency of insectoacaricides of different composition and manufacturers on flea eggs (Ctenocephalides spp.) for treatemnt of the premises where animals live. Materials and methods of the research. The study was conducted on the basis of the clinic of veterinary medicine "Vetservice" Sumy, laboratory "Veterinary Pharmacy" and "Innovative technologies and safety and quality of livestock products" of Sumy National Agrarian University. The ovicidal effect of insectoacaricides on flea eggs of Ctenocephalides spp. was studied. Ctenocephalides spp. eggs were selected from the pet bedding on which the animal spended most of its time, namely the cats. The studied material was selected with a cosmetic brush. Ctenocephalides spp. eggs were placed into a Petri dish of 10 eggs per each dish. The test material was introduced with a dental probe. There were 4 test dishes, which were treated with insectoacaricides (each test dish was treated with a separate drug) and 1 control dish with no treatment. Microscopy was conducted under a light microscope with magnification X8 of each egg, with following treatment of each egg with insectoacaricides. Monitoring was conducted in 24, 48 and 72 hours after treatment. Results. Research has shown that drugs which demonstrated 100 % ovicidal effectiveness were Sentry Home (pyriproxyfen – 0.02 %, permethrin – 0.2 %, n-Octyl Bicyclohepten – 1.0 %) in 24 hours and Neostomazan (CEVA)(transmix – 5.0 g, tetramethrin – 0.5 g) in 72 hours. Conclusions. Insectoacaricide drug Sentry Home (pyriproxyfen – 0.02 %, permethrin – 0.2 %, n-Octyl Bicyclohepten – 1.0 %), used for the treatment of the premises where the animals live, showed the most pronounced ovicidal effect in 24 hours.

The complete mitochondrial genome of the cat flea, Ctenocephalides felis

The cat flea, Ctenocephalides fells, is widely recognized as a global veterinary pest and a vector of pathogenic bacteria. We recently reported on the C. felis nuclear genome, which is characterized by over 38% protein coding gene duplication, extensive tRNA gene family expansion, and remarkable gene copy number variation (CNV) between individual fleas. Herein, we describe the assembly of the C. felis mitochondrial genome, a novel resource for comparative genomics of fleas and other insects. The order and content of mitochondrial genes is highly consistent with four previously sequenced flea mitochondrial genomes, limiting CNV to siphonapteran nuclear genomes.

A chromosome-level assembly of the cat flea genome uncovers rampant gene duplication and genome size plasticity

BACKGROUND

Fleas (Insecta: Siphonaptera) are small flightless parasites of birds and mammals; their blood-feeding can transmit many serious pathogens (i.e., the etiological agents of bubonic plague, endemic and murine typhus). The lack of flea genome assemblies has hindered research, especially comparisons to other disease vectors. Accordingly, we sequenced the genome of the cat flea, Ctenocephalides felis, an insect with substantial human health and veterinary importance across the globe.

RESULTS

By combining Illumina and PacBio sequencing of DNA derived from multiple inbred female fleas with Hi-C scaffolding techniques, we generated a chromosome-level genome assembly for C. felis. Unexpectedly, our assembly revealed extensive gene duplication across the entire genome, exemplified by ~ 38% of protein-coding genes with two or more copies and over 4000 tRNA genes. A broad range of genome size determinations (433-551 Mb) for individual fleas sampled across different populations supports the widespread presence of fluctuating copy number variation (CNV) in C. felis. Similarly, broad genome sizes were also calculated for individuals of Xenopsylla cheopis (Oriental rat flea), indicating that this remarkable "genome-in-flux" phenomenon could be a siphonapteran-wide trait. Finally, from the C. felis sequence reads, we also generated closed genomes for two novel strains of Wolbachia, one parasitic and one symbiotic, found to co-infect individual fleas.

CONCLUSION

Rampant CNV in C. felis has dire implications for gene-targeting pest control measures and stands to complicate standard normalization procedures utilized in comparative transcriptomics analysis. Coupled with co-infection by novel Wolbachia endosymbionts-potential tools for blocking pathogen transmission-these oddities highlight a unique and underappreciated disease vector.

Epizootic Situation of Feline Bartonella Infection in Eastern Poland

Introduction

The aim of the study was to establish the prevalence of Bartonella spp. in cats in eastern Poland, and to determine the factors associated with the infection.

Material and Methods

PCRs were performed to detect Bartonella DNA in the whole blood of 672 cats from four regions in eastern Poland (the Lublin, Podlasie, Masovian, and Subcarpathian provinces). The association between the previously selected variables and the dependent variable (presence of Bartonella DNA) was investigated using a logistic regression model.

Results

The overall prevalence of infection was 40.48%. All PCR positive cats were infected with B. henselae. The living conditions of the animals (free outdoor roaming), mixed breed cats, Subcarpathian region, and absence of tick control were significant risk factors associated with Bartonella infection at a 95% confidence level.

Conclusion

Cats in eastern Poland appear to be at risk of a bartonellosis epizootic. Factors which seem to impact the likelihood of infection in cats and factors which seem not to impact it have been suggested. We advocate additional research into the ways bartonellosis spreads, its geographical scope, and the factors that favour its development.

Evaluation of a plant-based food supplement to control flea populations in dogs: A prospective double-blind randomized study

A prospective double-blind randomized placebo-controlled study evaluated the tolerance and efficacy of the biological plant-based food supplement Bioticks® (extracts of thyme, rosemary, melissa, fenugreek, absinthe and lemongrass) as a flea-control product. Twelve dogs were used as placebo controls (group A). Ten dogs under similar housing conditions received the same food daily but supplemented with Bioticks® (group B). Flea counts were performed on D0 and 14, then 1, 2, 3, 4 and 5 months after the beginning of the study. No flea treatment was given or environmental modifications made during the 6 months prior to beginning and throughout the duration of the study. Efficacy was calculated according to Abbott's formula. No adverse event was recorded. At inclusion, dogs in groups A and B hosted a mean ± standard deviation of 7.9 ± 3.3 and 9.5 ± 3.6 fleas, respectively. The mean flea population in group A steadily increased until 4 months after D0 (21.5 ± 4.9 fleas/dog). Meanwhile, the mean flea population in group B dogs remained stable for the first month but then steadily decreased to reach an average of 3.1 ± 1.7 fleas/dog at D0+5 months. The percentage efficacy in the treated group as compared to the non-treated group was 33%, 51%, 71%, 80% and 82% at 1, 2, 3, 4 and 5 months, respectively.

Bioticks® was shown to be safe and effectively limited the flea population in dogs with a moderate flea infestation in conditions that were highly favourable to flea development. This is the first study to evaluate a plant-based product as an oral supplement for flea control.

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There is a growing demand for non-chemical, biological or “natural” flea products.

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In vivo studies assessing the efficacy of plant extracts are lacking in animals.

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The food supplement Bioticks® (Biodevas) contains several plant-extracts.

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Two groups of flea-infested dogs underwent a double-blind placebo-controlled study.

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Dogs fed with Bioticks® had a flea population reduced by 80% after 4 months.

2019 AAFP Feline Zoonoses Guidelines

AIM

The overarching purpose of the 2019 AAFP Feline Zoonoses Guidelines (hereafter referred to as the 'Guidelines') is to provide accurate information about feline zoonotic diseases to owners, physicians and veterinarians to allow logical decisions to be made concerning cat ownership.

SCOPE AND ACCESSIBILITY

The Panelists are physicians and veterinarians who worked closely together in an attempt to make these Guidelines a document that can be used to support the International One Health movement. This version of the Guidelines builds upon the first feline zoonosis panel report, published in 2003 ( catvets.com/guidelines ), and provides an updated reference list and recommendations. Each of the recommendations received full support from every Panelist. Primary recommendations are highlighted in a series of 'Panelists' advice' boxes.

DNA Vaccine Targeting Gonadotropin-Releasing Hormone Receptor and Its Application in Animal Contraception

Overpopulation of free-roaming and wildlife animals negatively affects economy and public health in many parts of the world. Contraceptive vaccines are viewed as a valuable option for reducing numbers of unwanted animals. This study develops vaccines for potential use in animal contraception exploiting a DNA platform. Objectives of the study were to generate DNA constructs directed against gonadotropin-releasing hormone receptor (GnRHR), a crucial molecular player in animal reproduction, and characterize them for ability to promote immune responses and suppression of reproductive parameters in vivo. DNA constructs were created to encode for a recombinant protein composed of two domains: GnRHR, the target antigen, and ubiquitin (Ub), a support protein. Ub-GnRHR constructs administered intramuscularly or intradermally or containing different promoters were compared. CMV and EF1α promoters were shown to be superior to CAG. In fertility trials, mice immunized intradermally with Ub-GnRHR construct driven by EF1α had a significantly lower number of fetuses. Importantly, the impaired fertility was achieved with a single DNA immunization and without the use of adjuvants. The study demonstrated for the first time that targeting the GnRH receptor with DNA-based vaccines could be a viable option for animal contraception.

A Bead-Based Flow Cytometric Assay for Monitoring Yersinia pestis Exposure in Wildlife

Yersinia pestis is the causative agent of plague and is considered a category A priority pathogen due to its potential for high transmissibility and the significant morbidity and mortality it causes in humans. Y. pestis is endemic to the western United States and much of the world, necessitating programs to monitor for this pathogen on the landscape. Elevated human risk of plague infection has been spatially correlated with spikes in seropositive wildlife numbers, particularly rodent-eating carnivores, which are frequently in contact with the enzootic hosts and the associated arthropod vectors of Y. pestis In this study, we describe a semiautomated bead-based flow cytometric assay developed for plague monitoring in wildlife called the F1 Luminex plague assay (F1-LPA). Based upon Luminex/Bio-Plex technology, the F1-LPA targets serological responses to the F1 capsular antigen of Y. pestis and was optimized to analyze antibodies eluted from wildlife blood samples preserved on Nobuto filter paper strips. In comparative evaluations with passive hemagglutination, the gold standard tool for wildlife plague serodiagnosis, the F1-LPA demonstrated as much as 64× improvement in analytical sensitivity for F1-specific IgG detection and allowed for unambiguous classification of IgG status. The functionality of the F1-LPA was demonstrated for coyotes and other canids, which are the primary sentinels in wildlife plague monitoring, as well as felids and raccoons. Additionally, assay formats that do not require species-specific immunological reagents, which are not routinely available for several wildlife species used in plague monitoring, were determined to be functional in the F1-LPA.

Comparative analysis of storage conditions and homogenization methods for tick and flea species for identification by MALDI-TOF MS

Ticks and fleas are vectors for numerous human and animal pathogens. Controlling them, which is important in combating such diseases, requires accurate identification, to distinguish between vector and non-vector species. Recently, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) was applied to the rapid identification of arthropods. The growth of this promising tool, however, requires guidelines to be established. To this end, standardization protocols were applied to species of Rhipicephalus sanguineus (Ixodida: Ixodidae) Latreille and Ctenocephalides felis felis (Siphonaptera: Pulicidae) Bouché, including the automation of sample homogenization using two homogenizer devices, and varied sample preservation modes for a period of 1-6 months. The MS spectra were then compared with those obtained from manual pestle grinding, the standard homogenization method. Both automated methods generated intense, reproducible MS spectra from fresh specimens. Frozen storage methods appeared to represent the best preservation mode, for up to 6 months, while storage in ethanol is also possible, with some caveats for tick specimens. Carnoy's buffer, however, was shown to be less compatible with MS analysis for the purpose of identifying ticks or fleas. These standard protocols for MALDI-TOF MS arthropod identification should be complemented by additional MS spectrum quality controls, to generalize their use in monitoring arthropods of medical interest.

The Biology and Ecology of Cat Fleas and Advancements in Their Pest Management: A Review

The cat flea Ctenocephalides felis felis (Bouché) is the most important ectoparasite of domestic cats and dogs worldwide. It has been two decades since the last comprehensive review concerning the biology and ecology of C. f. felis and its management. Since then there have been major advances in our understanding of the diseases associated with C. f. felis and their implications for humans and their pets. Two rickettsial diseases, flea-borne spotted fever and murine typhus, have been identified in domestic animal populations and cat fleas. Cat fleas are the primary vector of Bartonella henselae (cat scratch fever) with the spread of the bacteria when flea feces are scratched in to bites or wounds. Flea allergic dermatitis (FAD) common in dogs and cats has been successfully treated and tapeworm infestations prevented with a number of new products being used to control fleas. There has been a continuous development of new products with novel chemistries that have focused on increased convenience and the control of fleas and other arthropod ectoparasites. The possibility of feral animals serving as potential reservoirs for flea infestations has taken on additional importance because of the lack of effective environmental controls in recent years. Physiological insecticide resistance in C. f. felis continues to be of concern, especially because pyrethroid resistance now appears to be more widespread. In spite of their broad use since 1994, there is little evidence that resistance has developed to many of the on-animal or oral treatments such as fipronil, imidacloprid or lufenuron. Reports of the perceived lack of performance of some of the new on-animal therapies have been attributed to compliance issues and their misuse. Consequentially, there is a continuing need for consumer awareness of products registered for cats and dogs and their safety.

Molecular detection of vector-borne pathogens in Greek cats

Infectious diseases have been increasingly recognized in cats worldwide. The objective of this study was the molecular investigation of the prevalence of selected pathogens in healthy and sick cats from Greece, a country highly endemic for several canine vector-borne pathogens. Blood and/or bone marrow samples from 50 clinically healthy and 50 sick adult (>1 year-old) cats were retrospectively examined for the amplification of Bartonella spp., haemoplasmas, Ehrlichia spp., Anaplasma spp., Babesia spp., and Cytauxzoon spp. DNA. Overall, 14.9% of the cats were found to be infected or co-infected by haemoplasmas, including Candidatus Mycoplasma haemominutum and M. haemofelis. In addition, 8.5% of the cats were infected by Bartonella henselae, Bartonella clarridgeiae or Bartonella koehlerae. In contrast, DNA of Ehrlichia spp., Anaplasma spp., Babesia spp. and Cytauxzoon spp. was not amplified from the blood or bone marrow of any cat. There was no significant difference in either haemoplasma or Bartonella infection rates when comparing healthy and sick cats. This study represents the first description of Bartonella koehlerae in Greek cats.

Cats are not small dogs: is there an immunological explanation for why cats are less affected by arthropod-borne disease than dogs?

It is widely recognized that cats appear to be less frequently affected by arthropod-borne infectious diseases than dogs and share fewer zoonotic pathogens with man. This impression is supported by the relative lack of scientific publications related to feline vector-borne infections. This review explores the possible reasons for the difference between the two most common small companion animal species, including the hypothesis that cats might have a genetically-determined immunological resistance to arthropod vectors or the microparasites they transmit. A number of simple possibilities might account for the lower prevalence of these diseases in cats, including factors related to the lifestyle and behaviour of the cat, lesser spend on preventative healthcare for cats and reduced opportunities for research funding for these animals. The dog and cat have substantially similar immune system components, but differences in immune function might in part account for the markedly distinct prevalence and clinicopathological appearance of autoimmune, allergic, idiopathic inflammatory, immunodeficiency, neoplastic and infectious diseases in the two species. Cats have greater genetic diversity than dogs with much lower linkage disequilibrium in feline compared with canine breed groups. Immune function is intrinsically related to the nature of the intestinal microbiome and subtle differences between the canine and feline microbial populations might also impact on immune function and disease resistance. The reasons for the apparent lesser susceptibility of cats to arthropod-borne infectious diseases are likely to be complex, but warrant further investigation.

First detection of Candidatus Rickettsia barbariae in the flea Vermipsylla alakurt from north-western China

Background

Vermipsylla is a genus of the family Vermipsyllidae within the order Siphonaptera of fleas. Vermipsylla alakurt is mainly distributed in alpine pastoral areas of Kazakhstan, Mongolia, China and Nepal, and infests sheep, yaks and horses, causing irritation, poor condition, anaemia and even death. However, to date, no rickettsial agents have been reported in V. alakurt.

Findings

A total of 133 fleas were collected directly from the tails of three sheep flocks (n = 335) in Minfeng County, Xinjiang Uygur Autonomous Region, north-western China. Of these, 55 fleas were identified by morphological examination and molecular analysis of four loci (the ribosomal 18S and 28S rDNA genes and the mitochondrial genes cytochrome  c oxidase subunit II and elongation factor 1-alpha). Eight Rickettsia-specific gene fragments originated from seven genes: the 17-kilodalton antigen gene (17-kDa), citrate synthase gene (gltA), 16S rRNA gene (rrs), outer membrane protein A gene (ompA), surface cell antigen 1 gene (sca1), PS120 protein gene (gene D), and outer membrane protein B gene (ompB, two fragments), were used to identify the species of Rickettsia in 53 fleas. The amplified products were sequenced and included in a phylogenetic analysis to verify the taxonomic identification of the rickettsial agents. Based on morphological and molecular evidence, the flea was identified as Vermipsylla alakurt. Nine samples were positive (16.98 %, 9/53) for Rickettsia spp. The phylogenetic tree revealed that the rickettsial agents found in V. alakurt cluster with Candidatus Rickettsia barbariae.

Conclusions

Our study suggests that: (i) V. alakurt may serve as a carrier for Candidatus R. barbariae; and (ii) Candidatus R. barbariae, previously reported in Israel, is the eighth newly discovered validated Rickettsia species in China. This finding extends our knowledge of the distribution of Candidatus R. barbariae and the profile of carriers, which not only comprise ticks but also fleas.

Knock-down and speed of kill of a combination of fipronil and permethrin for the prevention of Ctenocephalides felis flea infestation in dogs

BACKGROUND

A topical combination of fipronil + permethrin (Frontline Tri-Act/Frontect, Merial) has recently been developed to control fleas, ticks, mosquitoes, sandflies and stable flies on dogs. Two studies were conducted to assess its speed of kill and knock-down effect on Ctenocephalides felis fleas. The combination was compared to either fipronil alone or to a combination of permethrin, dinotefuran, and pyriproxyfen,

METHODS

In each study, 18 dogs were randomly allocated to one of three groups: (Group 1: untreated dog; Group 2: treated once on D0 with the combination of fipronil and permethrin; Group 3: treated once on D0 either with fipronil alone (study 1) or with a combination of permethrin, dinetofuran and pyriproxyfen (study 2)). Each dog was infested with 100 unfed adult C. felis fleas on Days 2 (study 2), 7, 14, 21 and 28. Fleas were collected from dogs at 1 h and 12 h post- infestations (PI) (study 1) or at 2 h and 6 h PI (study 2) to assess efficacy and from collection pans underneath cages 1 h (study 1) or 5 min (study 2) PI to assess knock-down effect.

RESULTS

All treated dogs had significantly (p ≤ 0.01) lower flea counts than untreated dogs at every time point in both studies. For a whole month, a significant knock-down effect against infesting fleas is obtained in five minutes PI with the combination of permethrin and fipronil. Complete efficacy (>95%) was achieved in 1 h (study 1) or 2 h (study 2) PI for 14 days and by 6 h PI for all challenges conducted throughout the month. Efficacy remains >85% at 2 h PI for the whole month. A significantly higher efficacy of the fipronil + permethrin combination compared to other treatments was demonstrated at the earliest time points for the month (1 h knock-down effect and insecticidal efficacy compared to fipronil alone; 5 min knock-down effect compared to the combination of permethrin + dinetofuran + pyriproxyfen).

CONCLUSIONS

The rapid flea knock-down effect and speed of kill demonstrated by the spot on combination of fipronil + permethrin provide a reliable strategy against flea infestations in dogs.

Dynamics of Ctenocephalides felis felis (Siphonaptera: Pulicidae) Infestations on Urban Dogs in Southeastern Brazil

The cat flea, Ctenocephalides felis felis (Bouché, 1835), is an important ectoparasite of dogs and cats throughout the world, causing annoyance to the animals and acting as a vector of infections and a cause of allergic dermatitis in dogs and cats. Although climatic variability and seasonality are known to influence the diversity and abundance of fleas, few investigations of seasonal prevalence of cat flea infestation have involved the same group of dogs being examined regularly over an extended period. The aim of this study was to determine the effects of temperature, rainfall, and relative humidity on the infestation by C. felis felis on 88 outdoor dogs in southeastern Brazil. The dogs, which were of mixed breed, sex, and age, were examined for ectoparasites every month during the period August 2011 to July 2012, and samples of fleas were randomly collected and identified. Meteorological data, comprising mean temperature, total rainfall, and mean relative humidity, were recorded for the calendar month prior to that in which the examinations were performed. Dogs were found to be infested only with C. felis felis, with a higher prevalence in the months with lowest rainfall (July, August, and September). The data obtained in this investigation can be used in control programs in order to establish an efficient strategy for environmental management and the application of insecticides, particularly during the driest months of the year based on the seasonal pattern of infestation of dogs by C. felis felis.

Infection with Bartonella henselae in a Danish family

Bartonella species constitute emerging, vector-borne, intravascular pathogens that produce long-lasting bacteremia in reservoir-adapted (natural host or passive carrier of a microorganism) and opportunistic hosts. With the advent of more sensitive and specific diagnostic tests, there is evolving microbiological evidence supporting concurrent infection with one or more Bartonella spp. in more than one family member; however, the mode(s) of transmission to or among family members remains unclear. In this study, we provide molecular microbiological evidence of Bartonella henselae genotype San Antonio 2 (SA2) infection in four of six Danish family members, including a child who died of unknown causes at 14 months of age.

Pathogenic Landscape of Transboundary Zoonotic Diseases in the Mexico-US Border Along the Rio Grande

Transboundary zoonotic diseases, several of which are vector borne, can maintain a dynamic focus and have pathogens circulating in geographic regions encircling multiple geopolitical boundaries. Global change is intensifying transboundary problems, including the spatial variation of the risk and incidence of zoonotic diseases. The complexity of these challenges can be greater in areas where rivers delineate international boundaries and encompass transitions between ecozones. The Rio Grande serves as a natural border between the US State of Texas and the Mexican States of Chihuahua, Coahuila, Nuevo León, and Tamaulipas. Not only do millions of people live in this transboundary region, but also a substantial amount of goods and people pass through it everyday. Moreover, it occurs over a region that functions as a corridor for animal migrations, and thus links the Neotropic and Nearctic biogeographic zones, with the latter being a known foci of zoonotic diseases. However, the pathogenic landscape of important zoonotic diseases in the south Texas-Mexico transboundary region remains to be fully understood. An international perspective on the interplay between disease systems, ecosystem processes, land use, and human behaviors is applied here to analyze landscape and spatial features of Venezuelan equine encephalitis, Hantavirus disease, Lyme Borreliosis, Leptospirosis, Bartonellosis, Chagas disease, human Babesiosis, and Leishmaniasis. Surveillance systems following the One Health approach with a regional perspective will help identifying opportunities to mitigate the health burden of those diseases on human and animal populations. It is proposed that the Mexico-US border along the Rio Grande region be viewed as a continuum landscape where zoonotic pathogens circulate regardless of national borders.

Rabies prevention and management of cats in the context of trap-neuter-vaccinate-release programmes

Domestic cats are an important part of many Americans' lives, but effective control of the 60-100 million feral cats living throughout the country remains problematic. Although trap-neuter-vaccinate-return (TNVR) programmes are growing in popularity as alternatives to euthanizing feral cats, their ability to adequately address disease threats and population growth within managed cat colonies is dubious. Rabies transmission via feral cats is a particular concern as demonstrated by the significant proportion of rabies post-exposure prophylaxis associated with exposures involving cats. Moreover, TNVR has not been shown to reliably reduce feral cat colony populations because of low implementation rates, inconsistent maintenance and immigration of unsterilized cats into colonies. For these reasons, TNVR programmes are not effective methods for reducing public health concerns or for controlling feral cat populations. Instead, responsible pet ownership, universal rabies vaccination of pets and removal of strays remain integral components to control rabies and other diseases.

Faunal distribution of fleas and their blood-feeding preferences using enzyme-linked immunosorbent assays from farm animals and human shelters in a new rural region of southern Iran

Blood sucking insects, such as fleas, are responsible for the transmission of many infectious disease-causing agents which impose an intolerable burden on the health of people living particularly in endemic parts of the world. Fleas (Insecta: Siphonaptera) are found in many parts of the world including Iran. Both adult male and female fleas are obligatory ectoparasites. They are one of the main public health concerns as a result of their nuisance or the potential to act as vectors of a number of medically-important pathogens. The current study was conducted to examine the geographical distribution and fauna of fleas and their anthropophagic index in part of Fars province, southern Iran. This study was the first to be done in Iran. A total of 20 villages were randomly selected. From October 2011 to May 2012, adult fleas were collected by direct hand catch from human to animal shelters. Overall 848 fleas, most of which were blood-fed, were captured from the floor or the body of farm animal hosts (cattle, sheep, goat and hens). Only two different genera of fleas were identified, the main species (99.76 %) was human flea, Pulex irritans. The village of Shamsabad was the most heavily infested area. P. irritans had an anthropophagic index of 15 % using indirect enzyme-linked immunosorbent assays (ELISA). It could be concluded that P. irritans is widely distributed in this area. Based on their blood feeding activity, fleas thus posed a serious health threat to residents and their economically important livestock in this part of Iran.

An improved bioassay facilitates the screening of repellents against cat flea, Ctenocephalides felis (Siphonaptera: Pulicidae)

BACKGROUND

Repellents are a common method for preventing flea bites, making an effective system for flea repellent screening advantageous. We describe an improved technique to facilitate repellent activity screening of numerous plant-based Ctenocephalides felis (cat flea) repellents.

RESULTS

Two long strips of filter paper were impregnated with test compounds (dissolved in ethanol) and ethanol only, respectively. After drying, the two filter papers were glued together along the long side and inserted into a glass tube containing non-fed cat fleas. The distribution of cat fleas in each half of the filter paper was recorded after 30 min to calculate repellency. Results showed that the essential oil of Cinnamomum osmophloeum (from leaf), Taiwania cryptomerioides (from heartwood) and Plectranthus amboinicus (from leaf) exhibits repellent activity against cat fleas in a dose dependent manner. Moreover, the repellent activities against cat fleas of 2% trans-cinnamaldehyde (the main constituent of Ci. osmophloeum essential oil) and 0.5% thymol (the main constituent of P. amboinicus essential oil) are 97.6% and 90.6%, and can persist for up to 4 and 8 h, respectively. These results are comparable to those of 15% DEET.

CONCLUSION

The proposed screening technique can facilitate the pre-screening of numerous flea repellents for further evaluation on animal or human subjects.

Zoonotic diseases associated with free-roaming cats

Free-roaming cat populations have been identified as a significant public health threat and are a source for several zoonotic diseases including rabies, toxoplasmosis, cutaneous larval migrans because of various nematode parasites, plague, tularemia and murine typhus. Several of these diseases are reported to cause mortality in humans and can cause other important health issues including abortion, blindness, pruritic skin rashes and other various symptoms. A recent case of rabies in a young girl from California that likely was transmitted by a free-roaming cat underscores that free-roaming cats can be a source of zoonotic diseases. Increased attention has been placed on trap-neuter-release (TNR) programmes as a viable tool to manage cat populations. However, some studies have shown that TNR leads to increased immigration of unneutered cats into neutered populations as well as increased kitten survival in neutered groups. These compensatory mechanisms in neutered groups leading to increased kitten survival and immigration would confound rabies vaccination campaigns and produce naïve populations of cats that can serve as source of zoonotic disease agents owing to lack of immunity. This manuscript is a review of the various diseases of free-roaming cats and the public health implications associated with the cat populations.

Transmission of flea-borne zoonotic agents

Flea-borne zoonoses such as plague (Yersinia pestis) and murine typhus (Rickettsia typhi) caused significant numbers of human cases in the past and remain a public health concern. Other flea-borne human pathogens have emerged recently (e.g., Bartonella henselae, Rickettsia felis), and their mechanisms of transmission and impact on human health are not fully understood. Our review focuses on the ecology and epidemiology of the flea-borne bacterial zoonoses mentioned above with an emphasis on recent advancements in our understanding of how these organisms are transmitted by fleas, maintained in zoonotic cycles, and transmitted to humans. Emphasis is given to plague because of the considerable number of studies generated during the first decade of the twenty-first century that arose, in part, because of renewed interest in potential agents of bioterrorism, including Y. pestis.

Absence of zoonotic Bartonella species in questing ticks: first detection of Bartonella clarridgeiae and Rickettsia felis in cat fleas in the Netherlands

Background

Awareness for flea- and tick-borne infections has grown in recent years and the range of microorganisms associated with these ectoparasites is rising. Bartonella henselae, the causative agent of Cat Scratch Disease, and other Bartonella species have been reported in fleas and ticks. The role of Ixodes ricinus ticks in the natural cycle of Bartonella spp. and the transmission of these bacteria to humans is unclear. Rickettsia spp. have also been reported from as well ticks as also from fleas. However, to date no flea-borne Rickettsia spp. were reported from the Netherlands. Here, the presence of Bartonellaceae and Rickettsiae in ectoparasites was investigated using molecular detection and identification on part of the gltA- and 16S rRNA-genes.

Results

The zoonotic Bartonella clarridgeiae and Rickettsia felis were detected for the first time in Dutch cat fleas. B. henselae was found in cat fleas and B. schoenbuchensis in ticks and keds feeding on deer. Two Bartonella species, previously identified in rodents, were found in wild mice and their fleas. However, none of these microorganisms were found in 1719 questing Ixodes ricinus ticks. Notably, the gltA gene amplified from DNA lysates of approximately 10% of the questing nymph and adult ticks was similar to that of an uncultured Bartonella-related species found in other hard tick species. The gltA gene of this Bartonella-related species was also detected in questing larvae for which a 16S rRNA gene PCR also tested positive for "Candidatus Midichloria mitochondrii". The gltA-gene of the Bartonella-related species found in I. ricinus may therefore be from this endosymbiont.

Conclusions

We conclude that the risk of acquiring Cat Scratch Disease or a related bartonellosis from questing ticks in the Netherlands is negligible. On the other hand fleas and deer keds are probable vectors for associated Bartonella species between animals and might also transmit Bartonella spp. to humans.

One health: the importance of companion animal vector-borne diseases

The international prominence accorded the 'One Health' concept of co-ordinated activity of those involved in human and animal health is a modern incarnation of a long tradition of comparative medicine, with roots in the ancient civilizations and a golden era during the 19^th century explosion of knowledge in the field of infectious disease research. Modern One Health tends to focus on zoonotic pathogens emerging from wildlife and production animal species, but one of the most significant One Health challenges is rabies for which there is a canine reservoir. This review considers the role of small companion animals in One Health and specifically addresses the major vector-borne infectious diseases that are shared by man, dogs and cats. The most significant of these are leishmaniosis, borreliosis, bartonellosis, ehrlichiosis, rickettsiosis and anaplasmosis. The challenges that lie ahead in this field of One Health are discussed, together with the role of the newly formed World Small Animal Veterinary Association One Health Committee.

The cat flea (Ctenocephalides f. felis) is the dominant flea on domestic dogs and cats in Australian veterinary practices

This study was undertaken to determine the flea diversity on urban dogs and cats in Australia in 2009-2010. A total of 2530 fleas were recovered from 291 animals (151 dogs, 69 cats and 71 uncategorised dogs or cats) from veterinary clinics across five states of Australia. The majority of specimens were from coastal areas. The cat flea (Ctenocephalides felis felis) was the most frequent flea species identified (98.8%, 2500/2530). The only other flea species identified was the stickfast flea (Echidnophaga gallinacea) from Western Australia. Sequencing of the cytochrome oxidase subunit II mtDNA revealed a single haplotype across Australia within a subset of C. f. felis (n=19). Our study demonstrated dominance and haplotype homogeneity of C. f. felis on dogs and cats. Although Ctenocephalides canis was recovered from a feral fox, it was not identified from the sample of fleas analysed. This suggests that, under current conditions, it is unlikely that foxes are reservoirs of C. canis for domestic dogs or cats residing in coastal Australia, as previously speculated.