Distribution, prevalence, and genetic characterization of Baylisascaris procyonis in selected areas of Georgia.

Baylisascaris procyonis is an intestinal nematode of raccoons (Procyon lotor) that can cause fatal larval migrans in numerous species of birds and mammals, including humans. Although this parasite has historically been absent in the southeastern United States, it has been found in isolated regions in the Appalachian Mountains and was recently documented in DeKalb County, Georgia. The first objective of the current study was to investigate the distribution and prevalence of B. procyonis in selected populations of raccoons in Georgia. Intestinal tracts of 312 raccoons from 25 Georgia counties were examined for B. procyonis. The only county where B. procyonis was detected was Clarke County, where 12 of 116 (10.3%) raccoons were infected. In Clarke County, significantly more juveniles (P  =  0.049) were infected compared with adults, and no differences in prevalence were noted by sex, season of capture, or land use (rural vs. urban); however, significantly (P  =  0.0370) higher worm burdens were found in infected raccoons from urban/suburban locations compared with rural areas. In addition, Toxascaris leonina , a morphologically similar ascarid, was found in 3 raccoons from Clarke County (n  =  2) and Morgan County (n  =  1). A second objective was to determine if sequence polymorphisms were associated with B. procyonis from different geographic regions. Because sequences from a single worm from Japan had been entered into GenBank, we obtained nematodes from Kentucky and Texas for comparison with our samples from Georgia. Sequence analysis of the 18S and 5.8S rRNA genes and the internal transcribed spacer (ITS) -1 and ITS-2 regions confirmed Georgia samples were B. procyonis. Although several polymorphic bases were observed within both ITS regions, none was associated with a particular geographic location. These data indicate that the distribution of B. procyonis within Georgia is increasing and only limited genetic variation is present in the rRNA and ITS gene regions among B. procyonis from the southern United States and introduced populations in Japan.