Infestation of Rhipicephalus sanguineus sensu lato on cats in Malta

The Rhipicephalus sanguineus group: updated list of species, geographical distribution, and vector competence

The Rhipicephalus sanguineus group is an assembly of species morphologically and phylogenetically related to Rhipicephalus sanguineus sensu stricto. The taxonomy and systematics of this species group have remained obscure for a long time, but extensive research conducted during the past two decades has closed many knowledge gaps. These research advancements culminated in the redescription of R. sanguineus sensu stricto, with subsequent revalidation of former synonyms (Rhipicephalus linnaei, Rhipicephalus rutilus, and Rhipicephalus secundus) and even the description of new species (Rhipicephalus afranicus and Rhipicephalus hibericus). With a much clearer picture of the taxonomy of these species, we present an updated list of species belonging to the R. sanguineus group, along with a review of their geographic distribution and vector role for various pathogens of animals and humans. We also identify knowledge gaps to be bridged in future studies.

The detection of zoonotic microorganisms in Rhipicephalus sanguineus (brown dog ticks) from Vietnam and the frequency of tick infestations in owned dogs

Dog owners are greatly concerned about tick infestations in their pets. The prevalence and dispersion of ticks and their disease-causing microorganisms have been limited from the viewpoint of dog owners in Vietnam. This study investigated the presence of tick infestation and the pathogens associated with it in canines that were brought to veterinary hospitals in Vietnam. In the survey, 1,423 dogs participated from February to October 2022. Molecular and morphological methods were utilized to identify ticks and the associated pathogens. In addition,risk variables linked to tick infestation were documented and analyzed using statistical methods. The total exposure to the brown dog tick (Rhipicephalus sanguineus sensu lato) was 29.01%. Nam Dinh has the highest tick prevalence among the research areas. Tick infestation reached its highest point between June and September in the northern region of the country, with distinct seasons showing a strong correlation with tick infestation in dogs. Out of 177 tick pools examined, 146(82.49%) tested positive for at least one infection. Mycoplasma spp. (78.53%) was the most common, followed by Anaplasma spp. (37.29%), Rickettsia felis (5.08%), Babesia vogeli, and Hepatozoon canis (2.82%). In the current study, there was a statistically significant link between tick infestation and characteristics such as age, breed, body size, lifestyle, and bathing frequency. Understanding the seasonal behavior of vector ticks is crucial for identifying individuals or animals susceptible to tick-borne diseases. Studying the distribution of ticks and their ability to carry and disseminate zoonotic germs in specific places could assist veterinarians and policymakers in implementing effective strategies to manage zoonotic infections.

Molecular detection of vector-borne pathogens in cats tested for FIV and FeLV

The aim of this study was to detect molecularly vector borne pathogens (VBPs) in domiciled cats tested for Feline immunodeficiency virus (FIV) and Feline leukemia virus (FeLV). Blood samples (n = 119) were analyzed microscopically and molecularly through PCR and sequenced for the detection of the following pathogens: piroplasmids., Bartonella henselae, Cytauxzoon felis, Ehrlichia canis, Leishmania spp., hemotropic Mycoplasma spp., Trypanosoma spp., and Ricketssia spp. Animals were also serological assessed for detection of antibodies against FIV and FeLV. Out of all animals, 20.16% (24/119) tested positive for at least one VBPs at molecular examination. Conversely, no animal resulted positive at microscopic analysis. The most prevalent pathogen was hemotropic Mycoplasma haemofelis (8.40%; 10/119), followed by Candidatus Mycoplasma haemominutum (5.88%; 7/119), E. canis (5.04%; 6/119), C. felis (0.84%; 1/119) and B. henselae (0.84%; 1/119). One animal (0.84%; 1/119) was co-infected with. E. canis and B. henselae. A total of 5.88% (7/119) and 1.68% (2/119) tested positive for FIV and FeLV, respectively. Data of this study demonstrate that owned cats can be at risk of hemotropic Mycoplasma spp., E. canis, C. felis and B. henselae. Therefore, preventive measures against vectors of these pathogens should be implemented in order to reduce the risk of exposition and consequently infection. Additionally, aggressive behaviors among cats should be avoided, especially because hemotropic Mycoplasma spp. may be transmitted through the bite of animals.

Detection of zoonotic Bartonella species in ticks and fleas parasitizing free-ranging cats and dogs residing in temples of Bangkok, Thailand

Bartonellosis is a vector-borne disease caused by intraerythrocytic bacteria known as Bartonella spp. The potential vectors that transmit Bartonella spp. are fleas, ticks, sand flies, and lice. Several Bartonella spp. cause diseases in humans; however, there is few molecular evidence of Bartonella spp. in vectors in Thailand. The objectives of this study were to investigate Bartonella spp. and to evaluate the spatial distribution of Bartonella spp. prevalence in the ectoparasites parasitizing free-ranging cats and dogs in temple clusters of Bangkok, Thailand. In total, 343 ectoparasites were studied to extract their genomic DNA. Species of all specimens were identified using an identification key and conventional polymerase chain reaction (cPCR) was applied to confirm flea and tick species. Extracted DNA samples were processed using primers that targeted the gltA, rpoB, ftsZ, and ribC genes of Bartonella spp. Then, PCR-positive amplicons were sequenced and a phylogenetic tree was constructed. Recorded data were statistically analyzed using descriptive statistics, the chi-square test, Fisher's exact test, and the odds ratio. Area data were analyzed and a prevalence distribution map was plotted. The major parasitizing ticks and fleas in this study were Rhipicephalus sanguineus and Ctenocephalides felis, respectively. Overall, the prevalence of Bartonella spp. in ectoparasites was 7.00%. The gltA amplicons revealed the presence of B. henselae (4.78%) and B. clarridgeiae (4.78%) in C. felis, and B. koehlerae (1.25%) and B. phoceensis (1.25%) in R. sanguineus. Bartonella DNA was encountered in 16/39 (41.03%) districts and 28.57% of the temple clusters. Bang Khun Thian district had the highest positive proportion and Bang Bon district showed co-evidence of different Bartonella species. In addition, the intervening zones were a risk factor of Bartonella (p < 0.05), and the distribution map showed a scattered pattern of Bartonella-positive clusters. Finally, fleas showed to be important vector reservoirs for Bartonella spp., especially zoonotic species, however, experimental studies are needed to prove the Bartonella transmission in ticks.

Efficacy of a novel topical combination of esafoxolaner, eprinomectin and praziquantel against Rhipicephalus sanguineus in cats

Esafoxolaner is a purified enantiomer of afoxolaner with insecticidal and acaricidal properties. It is combined with eprinomectin and praziquantel in a novel topical endectoparasiticide formulation for cats. The efficacy of this novel formulation was assessed in an experimental study against induced infestation of Rhipicephalus sanguineus ticks. Twenty cats were randomly allocated to either a placebo control group or a treated group in a 1:1 ratio. Infested cats were treated topically once at the minimum recommended dose. The study was designed to assess curative efficacy 48 h after treatment and to test preventive efficacy 48 h after weekly infestations for 2 months. At each weekly infestation, all cats were infested with 25 male and 25 unfed female R. sanguineus ticks. At each tick count, at least 6 in 10 control cats had a retention of 13 (26%) or more live ticks, demonstrating adequate infestation throughout the study. Curative efficacy on existing tick infestation was 90%; preventive efficacy over the following 6 weeks was at least 96%.

Vector competence of Rhipicephalus sanguineus sensu stricto for Anaplasma platys

Anaplasma platys is a Gram-negative, obligate intracellular bacteria that causes canine infectious cyclic thrombocytopenia in dogs. The brown dog tick Rhipicephalus sanguineus sensu lato is presumed to be the vector of A. platys based on the overlap in distribution of R. sanguineus and A. platys infections, detection of A. platys DNA in both flat and engorged field-collected R. sanguineus, and the fact that dogs are primary hosts of both brown dog ticks and A. platys. However, the only study evaluating the vector competence of R. sanguineus for A. platys under controlled laboratory conditions reported an apparent inability of ticks to acquire or maintain the pathogen. In 2016, engorged female Rhipicephalus sanguineus sensu stricto ticks were collected off dogs to start a laboratory tick colony. After one generation of colony maintenance on tick-naïve and pathogen-free New Zealand White rabbits, a rabbit used to feed F1 adults seroconverted to Anaplasma phagocytophilum antigen. PCR and subsequent DNA sequencing identified the presence of A. platys in both the adult ticks fed on this rabbit and their resulting F2 progenies. Retrospective testing of all previous (P and F1) life stages of this colony demonstrated that the infection originated from one field-collected A. platys-infected female whose progeny was propagated in the laboratory and produced the PCR-positive F1 adults. Over the following (F2-F4) generations, the prevalence of A. platys in this colony reached 90-100 % indicating highly efficient transovarial and horizontal transmission, as well as transstadial maintenance, of this pathogen by R. sanguineus s.s.

First records and molecular-phylogenetic analyses of three tick species (Ixodes kaiseri, Hyalomma lusitanicum and Ornithodoros coniceps) from Malta

The Maltese islands are situated south of mainland Europe and north of Africa, therefore are expected to share tick species and tick-borne pathogens with both continents. This situation highlights the importance of studying ticks in this country. Nevertheless, the tick fauna of Malta appears to be a seldom investigated issue, with hitherto only five tick species reported in the country. Here, as part of a tick collection campaign continuing since 2016 in Malta, three tick species new to the country are reported and analyzed in comparison with GenBank data. Ixodes kaiseri (collected from North African hedgehog in Malta) had unique cytochrome c oxidase subunit I (cox1) and 16S rRNA gene haplotypes (with 98.1-99.3 % sequence identity to I. kaiseri from Europe and China). Phylogenetically, these haplotypes from Malta clustered separately from other, mainland-associated haplotypes, with high support. On the other hand, Ornithodoros coniceps (collected from domestic chicken in Malta) had identical or nearly identical cox1 and 16S rRNA gene haplotypes with soft ticks reported from France, northern Africa and western African islands, similarly to Hyalomma lusitanicum (collected from rabbit and cat in Malta) in comparison with conspecific ticks in Spain and Portugal. These results are most likely related to differences in host associations and corresponding translocality of these three tick species. Taken together, results of the present study add three new tick species to those five already known to be present in Malta.

Show us your ticks: a survey of ticks infesting dogs and cats across the USA

BACKGROUND

A variety of tick species infest dogs and cats in North America. Although most of these species also readily feed on people, national data regarding the species and abundance of ticks on dogs and cats are lacking. Here we report a large-scale study of ticks from dogs and cats in the USA over a 12-month period.

METHODS

Tick submissions were invited from veterinary practices in all 50 states. Ticks were submitted with information about the pet and the attachment sites of each tick marked on a biopsy chart. Upon receipt, ticks were identified to species and stage using morphologic keys; when necessary, species identification was confirmed molecularly.

RESULTS

From February 2018 through January 2019, 10,978 ticks were submitted from 1494 dogs and 336 cats in 49 states and ticks were collected in every month. Dog and cat infestation intensities ranged from 1 to 4765 and from 1 to 38 (median = 1, mean = 6.7 and 2.6), respectively. Dogs were primarily infested with Dermacentor variabilis (532/1494; 35.6%), Ixodes scapularis (409/1494; 27.4%), Amblyomma americanum (345/1494; 23.1%) and Rhipicephalus sanguineus (172/1494; 11.5%). Cats were primarily infested with I. scapularis (156/336; 46.4%), A. americanum (99/336; 29.5%) and D. variabilis (60/336; 17.9%). Other submitted ticks included A. maculatum, Haemaphysalis longicornis, Otobius megnini, and less common Dermacentor spp. and Ixodes spp. Co-infestations were documented in 93 dogs and 14 cats. Reported attachment sites of common tick species differed. In dogs, A. americanum was most commonly attached to the abdomen, axillary, and inguinal regions; D. variabilis and I. scapularis to the head, neck, and back; and R. sanguineus to the head, neck, abdomen, legs, and feet. In cats, I. scapularis was most commonly attached to the head and A. americanum was most commonly attached to the tail and perianal region.

CONCLUSIONS

These data confirm that dogs and cats in the USA are at risk of tick infestation throughout the year and that tick species present in the region have apparent attachment site preferences.