High prevalence of Sarcocystis and Trichinella infections in skeletal muscles of gray wolves (Canis lupus arctos) from Alaska, USA.

Although cysts of Sarcocystis spp. (sarcocysts) are considered uncommon in muscles of canids, we identified mature sarcocysts in tongues of 20 (40.8 %) of 49 gray wolves (Canis lupus arctos) from Alaska, USA. Two kinds of sarcocysts (thin-walled and thick-walled) were detected; based on the appearance of the sarcocyst wall, they resembled Sarcocystis caninum and Sarcocystis svanai of the domestic dog (Canis familiaris). Thick-walled cysts were identified in 18 of 49 wolves and thin-walled were seen in three of 49 wolves. Molecularly, Sarcocystis species were characterized using 18S rRNA, 28S rRNA, cox1 and rpoB genetic markers. All these markers showed >99 % identity to either of S. caninum or S. svanai described previously from the domestic dog. Trichinella spp. larvae were found in histological sections of tongues of 7 (14.2 %) of 49 gray wolves.