Beyond the Eye: Sarcocystis Infections in Lithuanian Cattle (Bos taurus) and Horses (Equus ferus caballus)

Sarcocystis are protozoan parasites with a mandatory two-host life cycle involving carnivores as definitive hosts and herbivorous or omnivorous animals as intermediate hosts. These parasites are of considerable veterinary and public health importance due to their widespread occurrence in livestock and their relevance to food safety. In cattle, three species are recognized as zoonotic or potentially foodborne (Sarcocystis hominis, Sarcocystis heydorni, and Sarcocystis bovifelis), and there have been sporadic reports of human food poisoning cases suspected to be associated with consumption of infected meat, including cases speculated to involve Sarcocystis bertrami from equine sources.

The present study aimed to investigate the occurrence and species diversity of Sarcocystis in cattle and horses in Lithuania using both microscopic and molecular approaches. Tissue samples were collected from cattle heart and diaphragm muscles, and from horses’ masticatory, cheek, and masseter muscles. All samples were examined microscopically for the presence of sarcocysts, and molecular analyses were performed to identify species richness within each investigated host.

Microscopic examination revealed the presence of sarcocysts in multiple muscle tissues of both host species. Molecular characterization confirmed the presence of distinct Sarcocystis species. In horses, Sarcocystis bertrami was identified, while in cattle, Sarcocystis cruzi and Sarcocystis bovifelis were detected.

These findings contribute to the understanding of Sarcocystis distribution in Lithuanian livestock and highlight the importance of combined microscopic and molecular diagnostic approaches for accurate species identification. The results also provide relevant data for veterinary parasitology and food safety.