Submitted to: American Journal of Tropical Medicine and Hygiene
Publication Type: Peer reviewed journal
Publication Acceptance Date: 1/5/1999
Publication Date: N/A
Citation: Interpretive Summary: Infections with the single-celled parasite Toxoplasma gondii are widely prevalent in livestock and humans in the U.S. Humans become infected mainly by ingesting food and water contaminated with oocysts (the resistant stage of T. gondii) or by ingesting tissue cysts of the parasite in uncooked meat. Scientists at the Beltsville Agriculture Research Center and the University of Illinois assessed T. gondii infection and risk factors associated with Toxoplasma infection in humans living and working on swine farms. They found that T. gondii antibodies were present in 31% of 174 humans surveyed. Factors associated with increased risk of T. gondii seropositivity were a higher number of T. gondii positive cats trapped on the farm, male sex, rearing pigs on pasture and gardening. These findings will be of interest to public health workers, veterinarians, physicians and pig farmers.
Technical Abstract: Risk factors for Toxoplasma gondii infection in workers and residents of swine farms were studied on 43 farms in Illinois. Blood samples were collected from 174 adults in 1993. The T. gondii seroprevalence was 31%. An interview was conducted with each participant, obtaining information on demographic characteristics and behaviors suspected to affect the risk of T. gondii infection. Factors associated with increased risk of T. gondii seropositivity were a higher number of seropositive cats trapped on the farm, male sex, rearing pigs on pasture and gardening. Factors associated with a decreased risk were handling of pig feed and presence of cats inside the pig facilities. Thus, infection of cats with T. gondii increased the risk of human infection, and contact with soil was a likely mechanism for transmission. The increased risk of seropositivity in males is attributed to less attention paid to cleanliness in food preparation and eating.