Seroprevalence of Toxoplasma gondii infection in domestic sheep in Durango State, Mexico.

The seroprevalence of Toxoplasma gondii infection in sheep (Ovis aries) in northern Mexico is largely unknown. Antibodies to T. gondii were determined in serum samples from 511 sheep from 8 farms in Durango State, Mexico, using the modified agglutination test (MAT). Sheep were raised in 3 geographical regions, i.e., mountainous (n  =  68), semi-desert (n  =  132), and valley (n  =  311). Overall, T. gondii antibodies were found in 77 (15.1%) of 511 sheep, with MAT titers of 1∶25 in 27, 1∶50 in 10, 1∶100 in 11, 1∶200 in 11, 1∶400 in 8, 1∶800 in 3, 1∶1,600 in 4, and 1∶3,200 in 3. The seroprevalence of T. gondii infection increased significantly with age, indicating post-natal transmission. In contrast, gender, breed, flock size, and geographic region did not significantly influence the seroprevalence. Seropositive sheep were found in 7 of 8 farms sampled. This is the first report of T. gondii infection in sheep in Durango State, Mexico. Results indicate that infected sheep are probably an important source of T. gondii infection for humans in Durango State.

Seroprevalence of Toxoplasma gondii infection in domestic goats in Durango State, Mexico.

Little is known concerning the seroprevalence of Toxoplasma gondii infection in goats in Mexico. Antibodies to T. gondii were determined in 562 goats in Durango, Mexico using the modified agglutination test. Goats were raised in 12 farms in two geographical regions: semi-desert (n=70) and mountains (n=492). Overall, antibodies to T. gondii were found in 174 (31%) of 562 goats, with titers of 1:25 in 18, 1:50 in 12, 1:100 in 10, 1:200 in 30, 1:400 in 32, 1:800 in 40, 1:1600 in 17, and 1:3200 or higher in 15. Seroprevalence of T. gondii increased with age, and varied with breed and geographic region; goats raised in the semi-desert region (Nubian breed) had a significantly higher seroprevalence (32.7%) than those raised in the mountains (mixed breed) (18.6%). Seropositive goats were found in all 12 (100%) farms sampled. This is the first report of T. gondii infection in goats in Durango State, Mexico. Results indicate that infected goats are likely an important source of T. gondii infection in humans in Durango State.

Seroprevalence of Toxoplasma gondii infection in domestic pigs in Durango State, Mexico.

Little is known concerning the prevalence of Toxoplasma gondii infection in pigs in Mexico. Accordingly, antibodies to T. gondii were determined in 1,074 domestic pigs in Durango, Mexico using the modified agglutination test. Two groups (A, B) of pigs were sampled: Group A pigs (n  =  555) were raised in 3 geographical regions in Durango State and Group B pigs (n  =  519) were from Sonora State but slaughtered in Durango City. Overall, antibodies to T. gondii were found in 136 (12.7%) of 1,074 pigs with titers of 1∶25 in 29, 1∶50 in 23, 1∶100 in 18, 1∶200 in 22, 1∶400 in 12, 1∶800 in 8, 1∶1,600 in 2, and 1∶3,200 or higher in 22. Of the pigs raised in Durango State, seroprevalence varied with age, management, and the geographic region; pigs raised in backyards in the mountainous region had a significantly higher seroprevalence (32.1%) than those raised in the valley (13.0%) and the semi-desert regions (14.0%). In Group A pigs from Durango, seroprevalence of T. gondii infection was significantly higher in pigs older than 8 mo (19.5%) than in younger pigs (10.9%). In the whole pig population (Groups A and B together), seroprevalence was higher in pigs raised in Durango (16.0%) than in those raised in Sonora (9.1%) and higher in mixed-breed pigs (15.7%) than in pure-bred pigs (10.3%). This is the first, in-depth study on the seroprevalence of T. gondii infection of pigs in Mexico and the first report on pigs from Durango State, Mexico. Results indicate that infected pork is likely an important source of T. gondii infection for humans in Durango State.