First molecular detection of Sarcocystis spp. in sheep from Aguascalientes, Mexico.

Sarcocystis spp. are widely distributed apicomplexan protozoa that infect sheep and other domestic animals. In Mexico, ovine sarcocystosis has been documented mainly through gross inspection and histopathology, while region-specific molecular data remain limited. In this study, we provide the first PCR-based molecular evidence of Sarcocystis spp. in sheep from Aguascalientes, Mexico. We processed 123 tissue samples (heart, esophagus, and liver) collected from 41 sheep slaughtered for human consumption. Parasite DNA was detected in 25/41 animals (60.9%). At the tissue level, PCR positivity was highest in the heart (18/41; 43.9%), followed by the esophagus (10/41; 24.4%) and the liver (4/41; 9.8%). Because PCR positivity indicates the presence of parasite DNA rather than confirmed tissue cysts, these results should be interpreted as molecular evidence of infection/exposure in the sampled population. This report provides a regional molecular baseline for follow-up studies in Mexico.