NEOSPORA-CANINUM ASSOCIATED EQUINE PROTOZOAL MYELOENCEPHALITIS

Equine protozoal myeloencephalitis (EPM) was clinically diagnosed in a 20-year-old horse with severe ataxia, The cerebrospinal fluid was pos itive for Sarcocystis neurona antibodies by western blot. The horse wa s administered corticosteroids to facilitate in vitro culture of S. ne urona from its spinal cord following necropsy, Microscopic lesions of EPM were present in the brain and in the spinal cord, including multif ocal inflammatory cellular infiltrates and several large groups of pro tozoa. Immunohistochemical, and light and electron microscopic examina tions revealed that the protozoa were Neospora caninum and not S. neur ona. The protozoa divided by endodyogeny, tachyzoites had rhoptries, a nd organisms reacted specifically to N. caninum antibodies. Veterinari ans should be aware of increasing diagnosis of N. caninum as another e tiological agent responsible for the lesions of EPM. (C) 1998 Elsevier Science B.V. AU rights reserved.