Meningoencephalitis Due to a Sarcocystis Neurona-like Protozoan in Pacific Harbor Seals (Phoca vitulina richardsi)

• DOI: 10.2307/3284670
• Publication Date: 2006-05-06T14:35:13Z
• Authors: Jean-Martin Lapointe; Padraig J. Duignan; Antoinette E. Marsh; Frances M. Gulland; Bradd C. Barr; Diane K. Naydan; Don P. King; Cindy A. Farman; Kathy A. Burek Hu...; Linda J. Lowenstine
• Keywords: Sarcocystosis

Seven Pacific harbor seals with meningoencephalitis associated Sarcocystis neurona-like protozoa are described. Six of the 7 were free-ranging and found stranded over an 80-km stretch central California coastline; other was captive. All had marked to severe nonsuppurative meningoencephalitis, most in cerebellar cortex. Immunohistochemistry for S. neurona antigens positive on brain tissue all cases, revealing numerous merozoites as well developing mature schizonts, including rosette forms. Electron microscopy performed 3 animals revealed schizonts consistent sp., absence rhoptries merozoites, lack a parasitophorous vacuole around division by endopolygeny. Serology using western blotting presence anti-S. immunoglobulins sera 4 5 tested. Four also concurrent mild moderate myocarditis; 1 seal, rare sarcocysts undetermined species present within cardiomyocytes.