HIGH PREVALENCE OF CYTAUXZOON FELIS IN BOBCATS (LYNX RUFUS) ACROSS OKLAHOMA AND OCCURRENCE IN WEST TEXAS, USA

Cytauxzoonosis is a fatal tick-borne disease in domestic cats caused by infection with the apicomplexan Cytauxzoon felis. Bobcats are the natural wild-vertebrate reservoirs for C. felis, and infections are typically subclinical and chronic in this species. The present study was done to determine the prevalence and geographic distribution of C. felis infection in wild bobcats from Oklahoma and the occurrence in northwestern Texas. Tongue samples from 360 bobcats were collected from 53 counties in Oklahoma and 13 samples from three counties in Texas. For DNA extracted from each tongue sample, a probe-based droplet digital PCR assay was performed targeting the C. felis mitochondrial gene cytochrome c oxidase subunit III (cox3). Prevalence of C. felis infection was calculated for each county sampled, and data from individual counties were combined according to geographic regions and compared using chi-square tests. Overall prevalence of C. felis in bobcats from Oklahoma was 80.0% (95% confidence interval [CI], 75.6-83.8). The prevalence of infection was >90% for bobcats from central, northeastern, south-central, and southeastern regions of Oklahoma, but <68% for bobcats from northwestern and southwestern regions. Bobcats from central counties in Oklahoma were 25.693 times more likely to be infected with C. felis compared to all other bobcats sampled from the state. Higher prevalence estimates of C. felis in bobcats appeared to be in counties where known tick vectors are most common. Occurrence of C. felis in bobcats from northwestern Texas was 30.8% (95% CI, 12.4%-58.0%) based on 13 samples. Results of this study support the utilization of bobcats as sentinel animals to identify geographic areas with risk of C. felis infection to domestic cats.