The host and parasite dynamics: Sarcoptic mange infestations among an urban coyote (Canis latrans) population
Ashlyn Halseth
Advisor: Stan Gehrt
Sarcoptic mange, caused by the obligatory ectoparasite, Sarcoptes scabiei var canis, poses significant threats to wild canid populations, as it results in high levels of morbidity and mortality. Despite its impact, the disease dynamics and individual risk of infestation for coyotes (Canis latrans) in urban environments remain understudied. As human density within urban spaces continues to rise globally, understanding how disease dynamics within coyote populations is crucial for both wildlife conservation and public health. The Cook County Coyote Project, spanning from 2000 to 2023, has been examining sarcoptic mange infestations among radio-collared coyotes within the Chicago metropolitan area. In this study, we aim to (1) determine prevalence rates, identify causes of mortality, and elucidate general disease dynamics of sarcoptic mange and (2) identify specific covariates that influence an individual’s likelihood of infestation within the Chicago coyote population. We found that sarcoptic mange prevalence was enzootic within our study site and was at a lower overall prevalence than studies conducted in rural areas. There was no significant increase in diagnoses between male and female coyotes; however, we were more likely to diagnosis coyotes with sarcoptic mange as adults than subadults or pups. 2% of the diagnosed coyotes fully recovered from gross lesions associated with sarcoptic mange. Coyotes that died from sarcoptic mange exposure were more common during the winter months. Individual likelihood of infestation was assessed using a generalized linear model using demographic and spatial covariates. Our best-fit model based on Akaike information criterion found that with a random effect for coyote ID, yearly home range composition and yearly age class were useful covariates in predicting individual risk of infestation; however, both fixed effects were non-significant. We hypothesize that sarcoptic mange infestations are rather influenced by inter-individual variation. Our research is novel in both the duration of the study period and the types of spatial covariates used. These advancements will contribute to illuminating the complex host-parasite dynamic of sarcoptic mange and coyotes in an understudied region of the coyote’s North American range.