Seroprevalence of Toxoplasma gondii infection in feral raccoons (Procyon lotor) in Japan.

Antibodies to Toxoplasma gondii were found in 92 (9.9%) of 929 feral raccoons (Procyon lotor) in Japan with the use of the latex agglutination test (LAT, 1:64 or higher). Seropositivity varied by geographic location, season, and weight of raccoons trapped. Seroprevalences in the northern, central, and western areas of Japan were found to be 7.9% (39/492), 16.5% (47/285), and 3.9% (6/152), respectively. The seroprevalence by season varied from 8.5% (13/153) in spring to 18.9% (14/74) in winter, which was significantly higher than those in other seasons (P < 0.05). Seroprevalence of T. gondii was elevated in accordance with the increase in body weight of raccoons (r(s) = 0.9), suggesting that the animals acquired the infection postnatally. The results suggest that the raccoon may serve as a useful indicator for the distribution of T gondii in peridomestic environments in Japan.