PATHOLOGY

Detailed explanation-1: -Rather, the protozoa are spread by the definitive host, the opossum, which acquires the organism from cats, raccoons, skunks and armadillos and possibly even from harbor seals and sea otters. The infective stage of the organism (the sporocysts) is passed in the opossum’s feces.

Detailed explanation-2: -Equine protozoal myeloencephalitis (EPM) is caused by the protozoal parasites Sarcocystis neurona and Neospora hughesi, although most cases are due to S. neurona. The definitive host for S. neurona is the opossum, and horses become infected when they ingest feed or water contaminated with opossum feces.

Detailed explanation-3: -Believe it or not, opossums don’t naturally carry the EPM parasite, but actually ingest it when eating decaying cats, skunks, and raccoons, which are key hosts for one phase of the parasite’s life cycle.