Prevalence of Sarcocystis spp. in two subspecies of caribou (Rangifer tarandus) in Newfoundland and Labrador, and foxes (Vulpes vulpes), wolves (Canis lupus), and husky dogs (Canis familiaris) as potential definitive hosts.

A study was conducted to determine the prevalence and geographical distribution of Sarcocystis spp. infecting 2 subspecies of caribou (Rangifer tarandus) inhabiting Newfoundland and Labrador and its potential definitive hosts. Muscle samples of caribou were obtained, primarily from hunters, and feces of red foxes (Vulpes vulpes) and wolves (Canis lupus), from trappers, and Husky dogs (Canis familiaris), from owners. Histological sections of muscle and flotation methods for feces were used for parasitic detection. Sarcocystis sp. infected more than 50% of barren-ground caribou (R. t. tarandus) from 4 locations in Newfoundland, but it was significantly greater in the north, where 99% of woodland caribou (R. t. caribou) from Labrador harbored the infection. Sporocysts were observed in 27 of 32 red foxes from eastern and northern Newfoundland, whereas 15 of 15 wolves and 22 of the 38 Husky dogs were infected. Wolves and red foxes probably acquired the infection through scavenging, and Husky dogs, from meat they were fed.