Geographic and temporal prevalence of Baylisascaris procyonis in raccoons (Procyon lotor) in Pennsylvania, USA.

In autumn of 2010 we collected fecal samples from the rectums of 89 trapped or road-killed Pennsylvania raccoons (Procyon lotor). Similar samples were collected in the summer and autumn of 2011 from 383 raccoons. Fecal samples were stored in 10% formalin until examined. Using saturated sugar flotation and a direct smear, we found Baylisascaris procyonis eggs in 38% of 2010 samples and 32.9% of 2011 samples. Prevalence in raccoons was greater in autumn than in summer and greater in juveniles than in adults; there was not a statistically significant difference between sexes. Infected raccoons were found in 54 of the 65 counties from which samples were recovered (a mean of 5.9 [range 1-12] raccoons were examined per county). The prevalences were similar in all regions of the state.