Fatal Hepatic Sarcocystosis in a Captive Black Bear (Ursus Americanus) Associated with Sarcocystis Canis-Like Infection

Abstract

Fatal hepatic sarcocystosis was diagnosed in a 13-year-old captive black bear ( Ursus americanus) with a history of acute onset of vomiting, polyuria, polydipsia, and bilirubinuria. Gross lesions included severe icterus, multisystemic hemorrhage, and gall bladder edema. The most significant microscopic lesion was severe necrotizing hepatitis with intralesional protozoa that reproduced by endopolygeny consistent with a Sarcocystis spp. Infrequent microglial nodules were randomly scattered within the white matter of the cerebral cortices, thalamus, and brainstem, but intralesional protozoal schizonts were not observed. In the liver, immunohistochemistry was positive for Sarcocystis spp. and negative for Toxoplasma gondii and Neospora spp. Positive staining was not observed in the brain. Genus-specific polymerase chain reaction (PCR) amplification of the 18S ribosomal RNA gene was performed on formalin-fixed, paraffin-embedded sections of liver and brain; in both tissues, PCR was positive for Sarcocystis spp. Sequence analysis of the PCR amplicons revealed 100% identity to the published sequences of Sarcocystis canis and Sarcocystis arctosi.

Fatal hepatic sarcocystosis in a free-ranging grizzly bear cub associated with Sarcocystis canis–like infection

“…In contrast to the positive result reported for the captive black bear, 3 the IHC test for Sarcocystis spp. in our grizzly cub was negative.…”

“…10,18 In contrast, the polar, black, and grizzly bears had both hepatic and encephalitic lesions suggestive of multisystemic disease, as has been reported for dogs infected with S. neurona. 5,7 Once considered a rare disease, hepatic sarcocystosis caused by a S. canis-like organism has now been reported in captive black bears, 3,23 captive polar bears, 11 and our freeranging grizzly bear cub. The presence of schizonts in the liver indicates that bears are acting as either an intermediate or aberrant host for this parasite.…”

Molecular diagnostics of Sarcocystis spp. infections

“…Other protozoa, from Apicomplexa phylum, were studied by the same fragment of rDNA (Morrison and Ellis 1997). This type of investigations were performed in numerous wild animals including pigeons (Columba livia f. domestica) (Olias et al 2009), black bears (Ursus americanus) (Davies et al 2011), raccoon dogs (Nyctereutes procyonoides) (Kubo et al 2010), sparrowhawks (Accipiter nisus) (Olias et al 2010), ducks (Anas platyrhynchos) (Kutkienl et al 2011), roe deers (Capreolus capreolus) (Dahlgren and Gjerde 2008), moose (Alces alces), red foxes (Vulpes vulpes) (Dahlgren and Gjerde 2010), wolverines (Gulo gulo) (Dubey et al 2010), vipers (Atheris nitschei) (Slapeta et al 2003), and otters (Enhydra lutris nereis) (Miller et al 2009).…”

Sarcocystis calchasi Outbreak in Feral Rock Pigeons (Columba livia) in California

“…DNA was extracted as previously described, 4 and a 521-bp portion of the 18S ribosomal RNA gene was amplified and sequenced. 1 The PCR was positive in 19 of 22 pigeons in either muscle (88%) or brain (68%) or both (59%) tissues (Suppl . Table S1).…”