A 1.5-year-old female red panda (Ailurus fulgens fulgens) presented for an acute left-sided head tilt, ataxia, and circling. Complete blood count and serum chemical analysis were unremarkable except for moderately increased alanine aminotransferase and aspartate aminotransferase. Cerebrospinal fluid (CSF) analysis showed a marked lymphocytic pleocytosis consistent with lymphocytic meningoencephalitis. Serologic testing for potential infectious causes such as Toxoplasma gondii, canine distemper virus, West Nile virus, and lymphocytic choriomeningitis virus was negative. Analysis of the CSF sample for T. gondii and Neospora caninum by polymerase chain reaction (PCR) and aerobic and anaerobic cultures was also negative. The red panda’s condition declined rapidly, and on the third day it was found to be moribund with paraparesis, anisocoria, and whole-body intention tremors. The red panda was humanely euthanized, and histopathology showed severe nonsuppurative meningoencephalitis with focal intralesional protozoan cysts and schizonts. The protozoan cysts were identified by PCR as Sarcocystis sp., most closely resembling S. tapai, S. ramphastosi, and S. neurona. Sarcocystis neurona is an apicomplexan coccidial parasite and is the causative agent of equine protozoal myeloencephalitis (EPM), a neurologic disease of horses that produces similar clinical signs including ataxia, asymmetric weakness, and cranial nerve deficits. Intermediate hosts are infected through ingestion of sporocysts shed in the feces of the opossum (Didelphis virginiana).1 Sarcocystis neurona-associated meningoencephalitis has been described in cats, mink, fisher, raccoons, striped skunks, ponies, Pacific harbor seals, and southern sea otters.1-3 To the authors’ knowledge, this is the first report of Sarcocystis-associated meningoencephalitis in a red panda.
1. Dubey, J.P., D.S. Lindsay, W.J.A. Saville, S.M. Reed, D.E. Granstrom, and C.A. Speer. 2001. A review of Sarcocystis neurona and equine protozoal myeloencephalitis (EPM). Vet. Parasitol. 95: 89–131.
2. Gerhold, R.W., E.W. Howerth, and D.S. Lindsay. 2005. Sarcocystis neurona-associated meningoencephalitis and description of intramuscular sarcocysts in a fisher (Martes pennanti). J. Wildl. Dis. 41: 224–230.
3. Thomas, N.J., J.P. Dubey, D.S. Lindsay, R.A. Cole, and C.U. Meteyer. 2007. Protozoal meningoencephalitis in Sea otters (Enhydra lutris): a histopathological and immunohistochemical study of naturally occurring cases. J. Comp. Path. 137: 102–121.