PREVALENCE OF TOXOPLASMA-GONDII INFECTIONS IN PENNSYLVANIA BLACK BEARS, URSUS-AMERICANUS

Serum samples from 665 hunter-killed black bears killed in 1989 to 199 2 throughout Pennsylvania (USA) were tested for Toxoplasma gondii anti bodies by the agglutination test in dilutions of 1:25, 1:50, and 1:500 . Toxoplasma gondii antibodies were found in 535 of 665 (80%) bears. C onsidering the highest dilutions at which antibodies were detected, pr evalences were 10% at 1:25, 37% at 1:50 and 33% at 1:500. No significa nt difference in antibody prevalence was found between males (79%) and females (80%), but a significant difference was found between juvenil e (65% and adult (83%) bears.