Detection of Sarcocystis spp. infection in bobcats (Lynx rufus).

The protozoan Sarcocystis neurona is an important cause of severe clinical disease of horses (called equine protozoal myeloencephalitis, EPM), marine mammals, companion animals, and several species of wildlife animals in the Americas. The Virginia opossum (Didelphis virginiana) is its definitive host in the USA and other animals act as intermediate or aberrant hosts. Samples of tongue and heart from 35 bobcats hunted for fur and food from Mississippi State, USA in February, 2014 were used for the present study. Muscles were examined for Sarcocystis infection by microscopic examination of either unfixed muscle squash preparations or pepsin digests, by histopathology of fixed samples, and by molecular methods. Sarcocystis-like bradyzoites were found in digests of 14 hearts and 10 tongues of 35 bobcats. In histological sections, sarcocysts were found in 26 of 35 bobcats; all appeared relatively thin-walled similar to S. felis sarcocysts under light microscope at 1000× magnification. S. neurona-like sarcocysts having thickened villar tips were seen in unstained muscle squash of tongue of two bobcats and PCR-DNA sequencing identified them definitively as S. neurona-like parasites. DNA extracted from bradyzoites obtained from tongue and heart muscle digests was analyzed by PCR-DNA sequencing at the ITS1 locus. Results indicated the presence of S. neurona-like parasite in 26 of 35 samples. ITS1 sequences identical to S. dasypi were identified in 3 bobcats, 2 of which were also co-infected with S. neurona-like parasite. The high prevalence of sarcocysts in bobcat tissues suggested an efficient sylvatic cycle of Sarcocystis spp. in the remote regions of Mississippi State with the bobcat as a relevant intermediate host.