Debilitation and mortality associated with besnoitiosis in four Virginia opossums (Didelphis virginiana).

Besnoitia spp. are coccidian parasites that infect a variety of wild and domestic mammals as well as some reptiles. Although infection with Besnoitia is common in Virginia opossums (Didelphis virginiana), clinical signs or death due to Besnoitia is rare. This manuscript describes four Virginia opossums that had severe clinical disease and inflammation associated with besnoitiosis. Clinical signs included trembling, incoordination, circling, blindness, poor body condition, and sudden death. Gross lesions included parasitic cysts in eyes, skin, and visceral organs. Histologically, cysts were often degenerate and associated with mild to marked inflammation, and amyloidosis was noted in one animal. Polymerase chain reaction and sequencing confirmed Besnoitia darlingi in three of the four opossums.