Submitted to: Avian Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 6, 1995
Publication Date: N/A
Interpretive Summary: Infections by the protozoan parasite of the genus Sarcocystis are widespread in livestock. Certain species of Sarcocystis can cause reduced growth, abortion and mortality in livestock. Little is known of clinical sarcocystosis in poultry. Scientists at the Beltsville Agricultural Research Center and the Mississippi State University report for the first time fatal sarcocystosis in a poultry flock in Mississippi. The findings will be of use to veterinary diagnosticians and poultry producers.
Sarcocystis-associated encephalitis was diagnosed in a backyard chicken flock with nervous manifestations. The main histopathologic lesion was necrotizing encephalitis characterized by foci of necrosis infiltrated and surrounded by mononuclear cells, heterophils, and multinucleated giant cells. Schizonts and merozoites were observed in the lesion. Immunohistochemical staining of the brain lesion revealed positive reaction to Sarcocystis antiserum. The ultrastructural characteristics of the parasite were typical of Sarcocystis including the presence of a nucleus, a conoid, numerous micronemes, and lack of rhoptries. Medication with amprol (amprolium) and sulfamethazine (sulmet) or terramycin (chlortetracycline) were not effective in controlling the mortality. Trapping of opossums on the farm and relocating the chickens to a new and clean premises, seemed to have reduced mortality from this infection.