Gray fox (Urocyon cinereoargenteus) identified as a new intermediate host for Sarcocystis neurona

Authors: Dubey, Jitender; GUPTA, ADITYA - Oak Ridge Institute For Science And Education (ORISE); CALERO-BERNAL, RAFAEL - Ciudad University - Spain; DE ARAUJO, LARISSA - Oak Ridge Institute For Science And Education (ORISE); GACÍA-GIL, MARÍA - Spanish National Microscopy Centre; BATTLE, JAQUIN - Oak Ridge Institute For Science And Education (ORISE); ANKRAH ANKARAH, AKO - Oak Ridge Institute For Science And Education (ORISE); VAN WHY, KYLE - US Department Of Agriculture (USDA); BROWN, JUSTINE - Pennsylvania State University; Rosenthal, Benjamin

Submitted to: Veterinary Parasitology: Regional Studies and Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/23/2024
Publication Date: 10/16/2024
Citation: Dubey, J.P., Gupta, A., Calero-Bernal, R., De Araujo, L., Gacía-Gil, M., Battle, J., Ankrah Ankarah, A., Van Why, K., Brown, J., Rosenthal, B.M. 2024. Gray fox (Urocyon cinereoargenteus) identified as a new intermediate host for Sarcocystis neurona . Veterinary Parasitology: Regional Studies and Reports. https://doi.org/10.1645/24-53.
DOI: https://doi.org/10.1645/24-53

Interpretive Summary: Parasites in the genus Sarcocystis impair livestock, wildlife health and can threaten food safety. Such parasites naturally cycle between carnivorous hosts and the herbivores upon which they prey. Therefore, USDA researchers endeavor to understand which of these parasites occur in food animals and seek to illuminate the diversity and relationships among parasites occurring in wildlife. One of these parasites, Sarcocystis neurona causes a neurological disease in horses (Equine Protozoal Encephalitis, or EPM), marine mammals and several other species of animals- research on this parasite was pioneered by researchers at APDL. Here they identified this parasite in muscles of gray fox for the first time. Ingestion of tissues of dead foxes by the opossum (the definitive host for S. neurona) can spread this parasite in the environment. These results will be of interest to veterinarians, and pathologists, and wildlife biologists.

Technical Abstract: The protozoan Sarcocystis neurona can cause severe disease in horses, marine mammals, and several other animal species in North America. The Virgina opossum (Didelphis virginiana) is its definitive host, and the raccoon (Procyon lotor) has been considered its primary intermediate host in the USA. Although canids have not previously been identified as important intermediate hosts for this parasite, we here report several natural cases in the gray fox (Urocyon cinereoargenteus). We identified muscular infections in 11 (23.9%) of 46 gray foxes from Pennsylvania, USA. In HE-stained sections of tongue and limb muscles, only 13 sarcocysts were detected in 7 of 46 foxes, in limb muscle of 4 and in tongue of 4. In hematoxylin and eosin-stained sections, the sarcocyst wall was up to 2.7 µm-thick and contained finger-like villar protrusions. In unstained muscle squashes, 44 sarcocysts were detected; they were up to 1200 µm long, 69 µm wide. From each infected fox, only one morphologic type of sarcocyst was found. By transmission electron microscopy, these sarcocysts appeared identical to those in animals experimentally with S. neurona. Molecularly, sarcocysts were characterized using 18S rRNA, 28S rRNA, cox1, ITS-1, rpoB, RON1, RON2, RON3, GAPDH1, ROP20, ROP21, ROP39, SnSRS21 and TUBA1; results confirmed the presence of S. neurona in the gray fox. This is the first report of muscular sarcocysts in the gray fox.