|DUBEY JITENER P|
|GAMBLE R HOWARD|
|HUMPHREYS J G|
Submitted to: American Journal of Veterinary Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/15/1994
Publication Date: N/A
Interpretive Summary: Infection by the parasites Toxoplasma gondii and Trichinella spiralis can cause serious illness in humans. Both infections can be acquired by ingesting undercooked meat harboring infectious stages. Little is known of T. gondii infections in bears. Scientists at the Beltsville Agricultural Research Center and the Indiana University of Pennsylvania have isolated for the first time viable Toxoplasma parasites from muscles of 5 of 89 bears killed by hunters during the 1992 hunting season. Trichina larvae were found in 2 of 63 bears. Therefore, all bear meat must be cooked thoroughly before human consumption.
Technical Abstract: During the hunting season of 1992, 322 black bears from Pennsylvania were examined for Toxoplasma gondii and Trichinella spp. infections. Toxoplasmas gondii antibodies were found in 79.8% of 322 bears in titers < 1:25 in 65 (20.2%), 1:25 in 18 (5.6%), 1:50 in 11 (34.5%) and 1:500 in 128 (38.7%) by the modified agglutination test. Muscle tissues from 89 of these bears were bioassayed for T. gondii parasites. Muscles from 64 bears including heart from 1, and heart alone from 1 bear were digested in pepsin, and the digested samples were bioassayed in mice. Toxoplasma gondii was isolated from 5 bears; from the heart of 1, heart and skeletal muscles of 1, and skeletal muscles of 3. The T. gondii antibody titers of the 5 bears with demonstrable T. gondii were: > 1:25 in all 5 bears by the modified agglutination test; < 1:10 (3 bears, considered negative), 1:20 and 1:320 by the Sabin-Feldman dye test; < 1:64 (3 bears, considered negative), 1:128, 1:512 by the indirect hemagglutination test and < 1:16 (2 bears, considered negative), 1:32, 1:64, and 1:512 by the latex agglutination test. Toxoplasma gondii was not isolated from feces of 5 cats fed muscles from the remaining 25 bears with T. gondii antibody titers of < 1:25. Antibodies against Trichinella were found in 6 (1.8%) of 319 bear sera; Trichinella spp larvae were demonstrated in muscles of 3 of 162 bears. Genetic typing indicated that the 2 isolates of Trichinella from bears were a sylvatic genotype and not the species found in the domestic pig.