The relationship of Baylisascaris procyonis to Illinois raccoons (Procyon lotor).

The gastrointestinal tracts of 310 steel-trapped or hunter shot Illinois raccoons (Procyon lotor) were collected in November and December 1979 and 1980 and examined for the presence of Baylisascaris procyonis (Nematoda) in order to determine the prevalence and intensity of this ascarid and to note any differences with respect to host age and sex. The raccoons were classified as either juveniles (animals less than 1 yr old) or adults. The prevalence for all the raccoons examined was 81.9% and is the highest reported in the United States when compared to other moderate to large samples. Juvenile raccoons had a significantly higher (P less than 0.0005) prevalence (93.5%) and mean intensity (62.4) than adults (55.3%; 11.8). Male raccoons had a significantly higher (P less than 0.025) prevalence (87.6%) than females (76.4%). Adult males had a significantly higher (P less than 0.05) prevalence (66.7%) than adult females (44.9%). In the other comparisons, no significant differences (P less than 0.05) in either prevalence or intensity were found. Since juveniles are more heavily infected than adults, they most likely pose a greater threat to other animals and humans as a potential cause of visceral larva migrans. It is advisable that all young raccoons kept as pets or in captivity be systematically and routinely treated with an appropriate anthelminthic to remove adult B. procyonis from the intestine.