Raccoon (Procyon lotor) Diets Shed Light on Baylisascaris procyonis Roundworm Prevalence

The raccoon, Procyon lotor, is the definitive host for raccoon roundworm (Baylisascaris procyonis), which causes a dangerous neurological disease known as larva migrans encephalopathy in intermediate hosts. As omnivores, raccoons rely on a variety of food items. Parasitized animals may exhibit altered eating habits and diets, and may undergo genetic variations as a result of parasite abundance. In this study, we analyzed the diets of necropsied raccoons from nine townships of Clark and Greene Counties, Ohio, by examining their stomach contents. We measured the mass of plant material found in raccoon stomachs and recorded the prevalence of B. procyonis. Mean mass of plant material varied among the nine townships surveyed (0.88g – 6.40g), indicating a correlation between raccoon diet and regional landscape. The townships with the least amount of agriculture had the greatest difference between all raccoons and B. procyonis infected raccoons (r²= 0.40). These results suggest that the complexity of raccoon diet exceeds that which can be explained by agricultural landscape alone. These findings help us better understand the relationship between B. procyonis and raccoon diet, therefore helping us to understand the ecological impacts of parasites on animal behavior.