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Oklahoma State University

Scientific Studies

OCS allows faculty and students the chance to expand on the current knowledge on colony and feral cats by participating in research studies. During each clinic we have between 100-200 cats which allow researchers an opportunity to learn something new. We hope this continued education on these special cats sparks more interest into an understudied population. Below is a list of research articles currently published and submitted to us by their authors. To read the full paper, please click on the paper's title to be directed to the research article. If you would like to perform your own research or have your published research listed below, please email us at

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Thomas, Staubus, Goolsby, & Reichard. (2016). Ectoparasites of free-roaming domestic cats in the central United States. Veterinary Parasitology, 228, 17-22.

Abstract: Free-roaming domestic cat (Felis catus) populations serve as a valuable resource for studying ectoparasite prevalence. While they share a similar environment as owned cats, free-roaming cats do not receive routine veterinary care or ectoparasiticide application, giving insight into parasite risks for owned animals. We examined up to 673 infested cats presented to a trap-neuter-return (TNR) clinic in the central United States. Ectoparasite prevalences on cats were as follows: fleas (71.6%), ticks (18.7%), Felicola subrostratus (1.0%), Cheyletiella blakei (0.9%), and Otodectes cynotis (19.3%). Fleas, ticks, and O. cynotis were found in all months sampled. A total of 1117 fleas were recovered from 322 infested cats. The predominate flea recovered from cats was Ctenocephalides felis (97.2%) followed by Pulex spp. (2.8%), Cediopsylla simplex (0.6%), and Nosopsyllus fasciatus (0.6%). A total of 373 ticks were recovered from 126 infested cats. The predominate tick species was Amblyomma americanum (65.9%) followed by Ixodes scapularis (32.5%), Dermacentor variabilis (10.3%), and Rhipicephalus sanguineus (0.8%). Immature tick stages accounted for 54.7% of all ticks found, highlighting an under-appreciated source of tick burden on domestic cats. The results of this study emphasize the importance of year-round use of ectoparasiticides with both insecticidal and acaricidal activity on domestic cats.

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Gruntmeir, J., Adolph, C., Thomas, J., Reichard, M., Blagburn, B., & Little, S. (2017). Increased detection of Dirofilaria immitis antigen in cats after heat pretreatment of samples. Journal of Feline Medicine and Surgery, 19(10), 1013-1016.

Abstract: Objectives: To determine whether pretreating diagnostic samples with heat increases the detection of Dirofilaria immitis antigen in adult cats, we evaluated feline serum and plasma samples collected in heartworm-endemic areas of the southern United States. Methods: Commercial microtiter well assays for detection of D immitis antigen were used to evaluate serum or plasma samples from 385 shelter and free-roaming cats from the southcentral and southeastern United States before and after heat treatment; commercial antibody tests were performed on a subset of samples. Results: Prior to sample heat treatment, 1/220 (0.5%) shelter cats and 4/165 (2.4%) free-roaming cats had detectable D immitis antigen. After heat pretreatment, the detection rate increased to 13/220 (5.9%) and 13/165 (7.9%), respectively. Antibody reactive to D immitis was significantly more common in the serum of cats that were antigen positive after heat treatment (10/13; 76.9%) than serum from cats that remained antigen negative after heat treatment (22/163; 13.5%). Conclusions and relevance: Heat pretreatment of feline samples increased antigen detection by commercial assays for D immitis and improved overall concordance of antigen and antibody test results in antigen-positive samples in this population. Although further work to investigate the specificity of D immitis antigen assays when using pretreated samples is warranted, this approach may be useful in the diagnosis of heartworm infection in individual cats and may increase the accuracy of surveys based on antigen detection.

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Johnson, E., Nagamori, Y., Duncan-Decocq, R., Whitley, P., Ramachandran, A., & Reichard, M. (2017). Prevalence of Alaria infection in companion animals in north central Oklahoma from 2006 through 2015 and detection in wildlife. Journal of the American Veterinary Medical Association, 250(8), 881-886.

Abstract Objective: To determine the prevalence of Alaria infection in cats and dogs in north central Oklahoma over various periods and investigate whether wild animal species in this region were also infected. DESIGN Combined cross-sectional study and case series. Sample: Results of parasitological testing of fecal samples from 5,417 client-owned dogs and 1,246 client-owned cats (2006 through 2014); fecal samples from 837 shelter or rescue dogs and 331 shelter or rescue cats (2013 and 2014) and 268 feral cats (2015); tongue or jowl samples from cadavers of 43 wild pigs, 3 opossums, and 1 raccoon; and intestinal tract segments from cadavers of 48 cats and 5 coyotes. Procedures: Various parasite recovery techniques were performed to detect various Alaria stages in samples. Recovered adult trematodes and mesocercariae were used for PCR assay and sequencing of the 28S rRNA gene. Results: Prevalence of Alaria infection was significantly higher in feral cats (9.0%) than in shelter or rescue cats (0.6%) and client-owned cats (1.4%) and in shelter or rescue dogs (1.8%) than in client-owned dogs (0.2%). Mesocercariae were recovered from tissue samples from 11 (26%) wild pigs and 1 opossum. Amplicon sequences from adult trematodes and mesocercariae were 100% identical to each other and 99% homologous to GenBank sequences of Alaria alata and Alaria mustelae. Conclusions and Clinical Relevance: Prevalence of Alaria infection in the study area has increased in dogs and cats since 1990, when infections were rare. Prevalence in wild pigs was similar to that in Eurasia, where A alata is considered an emerging zoonotic parasite.

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Nagamori, Y., Slovak, J., & Reichard, M. (2016). Prevalence of Cytauxzoon felis infection in healthy free-roaming cats in north-central Oklahoma and central Iowa. Journal of Feline Medicine and Surgery Open Reports, 2(1).

Abstract Case summary: Cytauxzoonosis is a tick-borne disease of cats, and Oklahoma (OK), USA, is considered an enzootic state. To determine the prevalence of Cytauxzoon felis, blood was collected from free-roaming cats, as they are frequently exposed to tick vectors. Our objective was to determine the prevalence of C felis infection in free-roaming cats in north-central Oklahoma and central Iowa (IA). Infection with C felis was determined using DNA extracted from blood and PCR amplification. Blood was collected from 380 free-roaming cats between January and April in 2014 in OK. DNA from C felis was detected in 3/380 (0.8%; 95% confidential interval [CI] 0.22–2.3%). In IA, 292 blood samples were collected between 2012 and 2014. No C felis-infected cats were detected (0; 95% CI 0–0%). Relevance and novel information: The prevalence of C felis (0.8%) in north-central OK reported herein was lower than the previously reported 3.4% in domestic cats in OK. Our study supports that the prevalence in a given enzootic area can vary by location and from the pool of cats sampled. None of 291 (0%) cats were infected with C felis in central IA. To date, only one case of cytauxzoonosis in a domestic cat has been reported in IA. It is important to monitor cats for C felis infections in northern US states, as geographic distribution of Amblyomma americanum expands northward. As free-roaming cats have more contact with the tick vectors of C felis, this population allows us to monitor the expansion of C felis distribution.

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