Sarcocystis neurona Transmission from Opossums to Marine Mammals in the Pacific Northwest

AbstractIncreasing reports of marine mammal deaths have been attributed to the parasiteSarcocystis neurona. Infected opossums, the only known definitive hosts, shedS. neurona sporocysts in their feces. Sporocysts can contaminate the marine environment via overland runoff, and subsequent ingestion by marine mammals can lead to fatal encephalitis. Our aim was to determine the prevalence ofS. neurona in opossums from coastal areas of Washington State (USA) and to compare genetic markers betweenS. neurona in opossums and marine mammals. Thirty-two road-kill opossums and tissue samples from 30 stranded marine mammals meeting inclusion criteria were included in analyses. Three opossums (9.4%) and twelve marine mammals (40%) were confirmed positive forS. neurona via DNA amplification at the ITS1 locus. Genetic identity at microsatellites (sn3, sn7, sn9) and the snSAG3 gene ofS. neurona was demonstrated among one harbor porpoise and two opossums. Watershed mapping further demonstrated plausible sporocyst transport pathways from one of these opossums to the location where an infected harbor porpoise carcass was recovered. Our results provide the first reported link betweenS. neurona genotypes on land and sea in the Pacific Northwest, and further demonstrate how terrestrial pathogen pollution can impact the health of marine wildlife.
Source: EcoHealth - Category: Environmental Health Source Type: research