Anaplasma bovis is primarily an infectious agent of ruminants, and has most commonly been reported in Asia, the Middle East, and Africa. Although the primary cause of human anaplasmosis is Anaplasma phagocytophilum, humans may rarely be infected by other Anaplasma spp. Human disease attributed to A. bovis has been occasionally reported, including an A. bovis-like agent in the United States. DNA of an A. bovis-like agent has been amplified from humans and the tick Dermacentor variabilis in the central region of the U.S., but larger prevalence studies among potential vectors or reservoir hosts in the U.S. have not been reported. The aim of this study was to evaluate the prevalence of A. bovis-like agent among D. variabilis and cattle in the Southcentral U.S. Previously extracted DNA from adult D. variabilis collected from Oklahoma (n = 38) and Kansas (n = 93), and blood of cattle from Oklahoma (n = 140) were tested by conventional PCR. Overall prevalence of A. bovis-like DNA within ticks was determined to be 3.1% (4/131), and all positive ticks originated from Oklahoma. Overall prevalence in bovine blood was determined to be 0% (0/140). These findings confirm the presence of an A. bovis-like agent, a potentially zoonotic pathogen, among ticks in the Southcentral U.S.; this agent is likely underrecognized and has been detected in parts of the U.S. that lie outside of the established geographic range for A. phagocytophilum. Further investigation and surveillance are necessary to elucidate possible reservoirs of A. bovis in the U.S., further evaluate the burden of human infection, and fully characterize genetic differences between the A. bovis-like agent detected in the U.S. and A. bovis in other regions of the world.

Vector-borne infections persist as a significant issue in both human and animal health. Many of the most common vector-borne infections in the USA, especially tick-borne infections, are known to be zoonotic, including Lyme disease, anaplasmosis, and ehrlichiosis, and these infections may also negatively impact the health of infected animals. Convenient patient-side assays for the detection of antibodies to Borrelia burgdorferi, Anaplasma spp., and Ehrlichia spp., and antigen of Dirofilaria immitis have allowed for the generation of robust and large-scale prevalence data in dogs. Data of similar scale and distribution are not available in cats, and most feline prevalence studies have evaluated a small sample size with limited geographic distribution. The objective of this study was to evaluate the prevalence of antibodies to B. burgdorferi, Anaplasma spp., and Ehrlichia spp., and D. immitis antigen among shelter cats across the USA, a population that is presumably at high risk for ectoparasitism and, consequently, exposure to vector-borne infections. In total, 2232 whole blood samples were collected from shelter cats across four regions of the USA—South, Northeast, Midwest, and West—and were evaluated using the Idexx SNAP^® 4Dx^® Test. Ectoparasites were also opportunistically collected from cats during blood collection and morphologically identified. The prevalence of at least one vector-borne infection was 2.60%, and the nationwide prevalence was 1.88% for B. burgdorferi, 0.54% for Anaplasma spp., 0.09% for Ehrlichia spp., and 0.55% for D. immitis. A total of 1120 ectoparasites were collected from 423 cats, including 27 ticks and 1093 fleas. Although the overall prevalence of the pathogens in this survey is relatively low, we observe that there is an increased exposure risk regionally for some agents, with geographic distributions in this study mostly coinciding with established human and canine distributions. Understanding these findings in an assumed non-protected population of cats allows us to extrapolate the risk to pet cats if they are not provided routine veterinary care, including a broad-spectrum parasite prevention program.

Background: Ixodid ticks and tick-borne diseases continue to be an emerging health concern in the USA. Companion animals dwell in close proximity with people; therefore, it is important to understand how they might contribute to the maintenance of tick-borne pathogens, especially zoonoses, in the peri-domestic environment. Domestic cats are often overlooked in epidemiological investigations of tick-borne infections compared with their canine counterparts. Methods: The purpose of this study was to investigate the potential exposure of domestic cats to tick-borne pathogens by molecularly testing adult Ixodid ticks collected from cats that were presented for veterinary care. A total of 802 ticks collected from 512 individual cats were tested by conventional polymerase chain reaction (PCR). Ticks were morphologically identified as Ixodes scapularis (n = 431), Amblyomma americanum (n = 218), and Dermacentor variabilis (n = 153). Results: The most prevalent pathogen detected was Borrelia burgdorferi s.s., detected in 19.5% of I. scapularis. Ehrlichia ewingii was detected in 3.2% of A. americanum. Anaplasma phagocytophilum was detected in 0.7% of I. scapularis. Cytauxzoon felis was detected in 0.5% of A. americanum. Borrelia miyamotoi was detected in 0.2% of I. scapularis. Submitting clinics were contacted to gather additional information on cats infested by pathogen-infected ticks. This information did not yield a meaningful relationship between potential pathogen exposure and development of clinical signs around the time of tick collection. Conclusions: This study is the largest survey for pathogens within Ixodid ticks collected from domestic cats in the USA and the only survey in which retrospective clinical information was retrieved. While the effect of many tick-borne pathogens on feline health remains unclear, this study demonstrates that cats infested with ticks are at risk for pathogen exposure and may be a source for harboring pathogen-infected ticks in and around the home. Graphical

Background: Canine leishmaniosis (CanL) is caused by Leishmania species. While vertical transmission is the primary route of CanL transmission in the USA, the role of sand fly vectors in its transmission and the prevalence in the broader pet population remain under-investigated. Diagnosis of CanL may include serology, PCR, or histopathology. However, ELISA tests are seldom used for the diagnosis of CanL in the USA despite their preference in endemic regions. Methods: Firstly, a serological and molecular survey was conducted in Oklahoma and Texas using the SNAP™ Leishmania Test (IDEXX Laboratories Inc.) on canine blood or serum, while serum only was used for commercial indirect immunofluorescence assay (IFA) testing. Molecular testing for Leishmania spp. included targeting segments of the small subunit rRNA gene by qPCR, the minicircle kinetoplast using a dPCR assay (QIAGEN), and a confirmatory Vector-borne Disease Panel (Antech Diagnostics). Secondly, sand fly trapping and testing were conducted in Oklahoma and Texas with morphological and molecular identification targeting the ITS-2 gene, as well as qPCR for Leishmania spp. Finally, a nationwide serological survey of apparently healthy dogs was conducted using the SNAP Leishmania Test and confirmatory testing with a commercial IFA test. Results: In the regional survey, seroprevalence was 0.61% (2/328; CI 0.07–2.0) with the SNAP Leishmania Test and 4.35% (6/138; CI 2.0–9.0) via the IFA test. Leishmania spp. DNA was not detected in any of the tested blood samples ( n = 253). Psathyromyia shannoni ( n = 8) were collected from Denton and Grayson Counties, Texas, with no detection of Leishmania spp. DNA. The nationwide prevalence of Leishmania spp. antibodies was 0.35% (9/2,515; CI 0.16–0.68) in non-Foxhound pet dogs from 48 states. Notably, all positive samples on the SNAP Leishmania Test were positive on IFA testing. Conclusions: Leishmania seropositive animals were found in Texas and Oklahoma, as other infections were demonstrated by the vector-borne panel. The sand fly vector role could not be determined due to limited collection of specimens. Nationwide survey demonstrated a low prevalence of Leishmania antibodies. The methods used in this study (SNAP Leishmania Test and IFA) constitute useful tools for canine leishmaniosis surveys, and sample choices should be taken into account.

Tick-borne diseases predominate among vector-borne diseases of human and veterinary importance in the United States (US). Many of the most important tick-borne agents in people, including Borrelia burgdorferi, Anaplasma spp., and Ehrlichia spp. are zoonoses capable of infecting domestic pets. These infections can impact animal health with widely varying severity, ranging from subclinical to life-threatening disease. Serological testing is essential for screening and diagnosis of these infections in pets, as well as for epidemiological investigations. While vast amounts of data are available on the seroprevalence of antibodies to B. burgdorferi, Anaplasma spp., and Ehrlichia spp. in domestic dogs, comparatively little data is available in domestic cats. The purpose of this study was to evaluate the prevalence of antibodies to B. burgdorferi, Anaplasma spp., and Ehrlichia spp., as well as antigen of D. immitis, the causative agent of heartworm disease, in a population of apparently healthy pet cats from across the US using the point-of-care (POC) SNAP® 4Dx® PLUS test. This POC test does not visually distinguish between antibodies within the Anaplasma genus and antibodies within the Ehrlichia genus. To address this, additional specific peptide testing was conducted at IDEXX Laboratories for Anaplasma spp. and Ehrlichia spp. seropositive samples. In total, n = 1572 feline serum samples were tested using the SNAP® 4Dx® PLUS. All US states were represented by at least 3 samples, and 2.6 % of cats demonstrated evidence of exposure to ≥1 vector-borne pathogen. Cats in the present study were most commonly exposed to Anaplasma spp. (1.40 %), which contrasts previous seroprevalence reports in cats, in which B. burgdorferi predominates. Seroprevalence of Anaplasma spp. was followed by B. burgdorferi (1.15 %), Ehrlichia spp. (0.38 %), and lastly D. immitis antigen detection (0.13 %). Feline exposure to tick-borne agents observed in the present study was compared with canine seroprevalence reported by the Companion Animal Parasite Council over the same time period. We found that feline exposure was 14-28 % of the exposure prevalence reported in dogs. Although less common than canine infection, continued investigation into feline infection with B. burgdorferi, Anaplasma spp., and Ehrlichia spp. is warranted. Feline susceptibility to these agents, transmission dynamics, pathogenicity, and immunologic response remain poorly described.

We developed and validated a real-time PCR to detect an Anaplasma bovis-like agent. We applied that assay to 672 Dermacentor spp. ticks collected from across the United States and found 0.1% A. bovis-like agent prevalence. This assay could enhance epidemiologic surveys for this A. bovis-like agent in ticks and humans.