Seroprevalence of Toxoplasma gondii infection in dairy goats in Michoacán State, Mexico.

Seroprevalence of Toxoplasma gondii infection in goats in Michoacán, Mexico, is largely unknown. Antibodies to T. gondii were determined in 341 dairy goats in Michoacán, Mexico, using the modified agglutination test. Goats were raised in 9 farms in 6 municipalities. Overall, antibodies to Toxoplasma were found in 52 (15.2%) of 341 goats, with titers of 1:25 in 16, 1:50 in 9, 1:100 in 4, 1:200 in 4, 1:400 in 4, 1:800 in 9, 1:1,600 in 3, and 1:3,200 or higher in 3. Seropositive goats were found in all 9 farms sampled, and seroprevalence varied significantly among farms (1.9-90%). Seroprevalence of T. gondii varied with age, municipality, altitude, and climate but not with breed. Increased seroprevalence was found in goats aged 13-24 and 49-86 mo old (25% and 22.9%, respectively). Goats raised in farms in a municipality with semi-warm humid climate at 1,700 m of altitude had the highest seroprevalence (62.1%). This is the first report of T. gondii infection in goats in Michoacán State, Mexico, and of an association of seropositivity to T. gondii and semi-warm humid climate. Results indicate that infected goats are likely an important source of infection with T. gondii in humans in Michoacán State.