Zoonotic Sarcocystis hominis and Sarcocystis heydorni in a Bovine Carcass: First Report in Portugal.

During routine meat inspection, eosinophilic myositis-like lesions were detected in the masseter muscles of a 55-month-old bovine, leading to partial condemnation of the head. The lesions appeared as multiple round, yellowish-green areas, suggestive of a parasitic aetiology. Histopathological and molecular analyses were performed, and PCR sequencing identified Sarcocystis hominis, S. cruzi and S. heydorni. Of these, S. hominis and S. heydorni are zoonotic. Humans may acquire infection by consuming raw or undercooked beef containing viable sarcocysts. To the best of our knowledge, this is the first report of zoonotic Sarcocystis in cattle in Portugal. These findings underscore the importance of meat inspection as a tool for active surveillance and for protecting both animal and public health.