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

Authors

Camila K. Cerqueira-Cézar, United States Department of Agriculture, Beltsville Agricultural Research Center, Building 1001, Beltsville
Peter C. Thompson, United States Department of Agriculture, Beltsville Agricultural Research Center, Building 1001, BeltsvilleFollow
Shiv Kummar Verma, United States Department of Agriculture, Beltsville Agricultural Research Center, Building 1001, Beltsville
Joseph Mowery, Beltsville Agricultural Research Center, Building 12, Beltsville
Rafael Calero-Bernal, United States Department of Agriculture, Beltsville Agricultural Research Center, Building 1001, Beltsville
Fernando H. Antunes Murata, United States Department of Agriculture, Beltsville Agricultural Research Center, Building 1001, Beltsville
David R. Sinnett, United States Department of Agriculture, 9001 E. Frontage Rd, Palmer
Caroline Van Hemert, United States Geological Survey, Alaska Science Center
Benjamin M. Rosenthal, United States Department of Agriculture, Beltsville Agricultural Research Center, Building 1001, Beltsville
Jitender P. Dubey, United States Department of Agriculture, Beltsville Agricultural Research Center, Building 1001, BeltsvilleFollow

Document Type

Article

Date of this Version

5-15-2017

Citation

Springer-Verlag Berlin Heidelberg (outside the USA) 2017

Comments

Parasitol Res (2017) 116:1871–1878 DOI 10.1007/s00436-017-5462-6

Abstract

The muscles of herbivores commonly harbor sarcocysts of parasites belonging to species in the genus Sarcocystis, but such muscle parasites are rare in carnivores. Here, we report Sarcocystis arctica-like sarcocysts in muscles of Arctic foxes (Vulpes lagopus) from Alaska, USA, for the first time. The tongues of 56 foxes were examined for Sarcocystis infection using several methods. Sarcocystis bradyzoites were detected in pepsin digests of 13 (23.2%), and sarcocysts were found in histological sections stained with hematoxylin and eosin (HE) of 9 (16.0%). By light microscopy, sarcocysts were up to 4 mm long and up to 245 μm wide. In HE-stained sections, the sarcocyst wall appeared smooth and up to 1.5 μm thick without visible protrusions. 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 9c.” All sarcocysts were mature and contained numerous 8.1 × 2.1 μm sized bradyzoites. Molecular characterization (at 18S rDNA, 28S rDNA, ITS- 1, and cox1) showed the highest affinity for S. arctica of the Arctic fox (V. lagopus) from Norway. In the present investigation, we provide evidence that sarcocysts are common in tongues of Alaskan Arctic foxes suggesting that these carnivores are serving as intermediate hosts, and we also provide ultrastructure of S. arctica from the Arctic fox for the first time.