Submitted to: Journal of Eukaryotic Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 15, 1996
Publication Date: N/A
Interpretive Summary: Infection by the protozoan parasite, Toxoplasma gondii causes metal retardation and loss of vision in children and abortion livestock. Humans become infected with T. gondii by ingesting infected meat, by ingesting food and water contaminated with oocysts from feces of infected cat feces, or congenitally. Infected pigs are considered as an important meat source of Toxoplasma for humans. Scientists at the Beltsville Agricultural Research Center and the University of Illinois have determined that cats infected with T. gondii are the main source of infection for pigs on Illinois farms. The results will be of interest to the public health workers and veterinarians.
Pigs are considered an important meat source of Toxoplasma gondii infection for humans in the U.S. In one survey, viable T. gondii was isolated from 17% of 1000 sows from Iowa. To determine risk factors for transmission of T. gondii, field studies were conducted on 47 swine farms in Illinois. Antibodies to T. gondii (titer > 25, direct agglutination test) were found in 97 of 4,252 (2.3%) finishing pigs, 395 of 2,617 (15.1%) sows, 267 of 391 (68.3%) cats, 126 of 188 (67.0%) raccoons, 7 of 18 (38.9%) skunks, 29 of 128 (22.7%) opossums, 6 of 95 (6.3%) rats, 3 of 61 (4.9%) white-footed mice (Peromyscus sp.), and 26 of 1,243 (2.1%) house mice (Mus musculus). Viable Toxoplasma gondii was recovered from tissues of 7 of 1,502 (0.5%) house mice, 2 of 67 (3.0%) white-footed mice and 1 of 107 (0.9%) rats. Toxoplasma gondii was isolated from 2 of 491 (0.4%) feed samples, 1 of 79 (1.3%) soil samples, and 5 of 274 (1.8%) samples of cat feces. Evaluation of all risk factors indicated that infected cats and mice were the main risk for transmission of T. gondii to pigs.