Morphological and molecular characterization of Sarcocystis arctica-like sarcocysts from the Arctic fox (Vulpes lagopus)from Alaska, USA

Authors: CEZAR, CAMILA - Non ARS Employee; THOMPSON, PETER - Non ARS Employee; VERMA, SHIV - Non ARS Employee; MOWERY, JOSEPH - Non ARS Employee; CALER-BERNAL, RAFAEL - Non ARS Employee; SINNETT, DAVID - Animal And Plant Health Inspection Service (APHIS); VAN HEMERT, CAROLINE - Us Geological Survey (USGS); Rosenthal, Benjamin; Dubey, Jitender

Submitted to: Veterinary Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/24/2017
Publication Date: 5/15/2017
Citation: Cezar, C., Thompson, P., Verma, S., Mowery, J., Caler-Bernal, R., Sinnett, D., Van Hemert, C., Rosenthal, B.M., Dubey, J.P. 2017. Morphological and molecular characterization of Sarcocystis arctica-like sarcocysts from the Arctic fox (Vulpes lagopus)from Alaska, USA. Veterinary Parasitology. 116:1871-1878. https://doi.org/10.1007/s00436-017-5462-6
DOI: https://doi.org/10.1007/s00436-017-5462-6

Interpretive Summary: Toxoplasma and Sarcocystis are related single celled parasites of livestock and humans. While Toxoplasma has long been recognized to cause neurologic disease in many warm blooded hosts, several species of Sarcocystis also cause a variety of disorders in livestock, pets, and wild animals and some of them are zoonotic. The Arctic fox ( Vulpes lagopus) is listed as endangered in some countries and wildlife biologists are attempting to find causes of death for this fox. In the present paper, the authors found that Sarcocystis was common (22.8% of 57) in muscles of Arctic foxes from Alaska, USA. Here they described morphologic and molecular criteria to characterize the species of Sarcocystis (Sarcocystis arctica) they found. The results will be of interest to biologists, zoo veterinarians, and parasitologists, and help diagnosis of sarcocystosis.

Technical Abstract: Sarcocystis sarcocysts are common in muscles of herbivores but are rare in muscles of carnivores. Here, we report Sarcocystis arctica-like sarcocysts in muscles of Arctic foxes (Vulpes lagopus) from Alaska, USA for the first time. Tongues of 57 foxes were examined for Sarcocystis infection using several methods. Sarcocystis bradyzoites were detected in pepsin digests of 13 (22.8%), and sarcocysts were found in histological sections stained with hematoxylin and eosin (HE) of 9 (15.7%). By light microscopy, sarcocysts were up to 4 mm long and up to 245 µm wide. In HE –stained sectionsthe sarcocyst wall appeared smooth and up to 1.5 µm thick without visible. By transmission electron microscopy, the sarcocyst wall had a wavy parasitophorous vacuolar membrane (pvm) folded as pleomorphic villar protrusions (vp), sometimes with anastomoses of villar tips. The vp and the ground substance (gs) layer were smooth and without microtubules. The gs was up to 2.0 µm thick. The total width of the wall including vp and the gs was up to 4.0 µm. The vp were up to 3.0 µm long and most closely resembled “type 9 c”. All sarcocysts were mature and contained numerous 8.1x 2.1 µm sized bradyzoites. Molecular characterization showed the highest identity for 18S rDNA, 28S rDNA, ITS-1, and cox1 sequences of Sarcocystis arctica of the Arctic fox (Vulpes lagopus) from Norway. Results of the present investigation indicate that sarcocysts are common in tongues of Arctic foxes in Alaskae and we also provide ultrastructure of S. arctica from the Arctic fox for the first time.