Broad host specificity of Trichinella chanchalensis and minimal interspecific competition with T. nativa and T6 in naturally co-infected hosts

Trichinella are muscle-dwelling parasitic nematodes that infect a wide range of vertebrate hosts, including humans. Trichinella chanchalensis is a newly recognized species that has been reported in wolverine (Gulo gulo). To investigate the host range of T. chanchalensis we examined the tongue and/or diaphragm from 125 wolverines, 34 red foxes (Vulpes vulpes), 23 Canada lynx (Lynx canadensis), 13 grey wolves (Canis lupus), 10 coyotes (Canis latrans), six black bears (Ursus americanus), one grizzly bear (Ursus arctos), and one polar bear (Ursus maritimus), from Yukon, Canada. Larvae were recovered from tissues by artificial digestion, quantified as larvae per gram (LPG), and genotyped using next-generation sequencing (NGS) on pools of larvae. The parasite intensity of three Trichinella species/genotypes (T. nativa, Trichinella T6, T. chanchalensis) in each sample was estimated by multiplying LPG and relative abundance. Trichinella larvae were detected in 74 % (158/213) of animals and prevalence ranged from 16.7 % in black bears to 86.4 % in wolverines. Median infection intensity was highest in wolverines (13.5 LPG) and lowest in lynx (1.2 LPG), and 92 % of hosts were co-infected with ≥ 2 Trichinella species/genotypes. The parasite intensity of Trichinella T6 was two times greater than T. nativa, and 17 times greater than T. chanchalensis. Trichinella chanchalensis was detected in three new host species including lynx, wolves, and a coyote. There was no significant interaction between Trichinella species/genotype and host species which suggests minimal host specificity. The parasite intensities of T. nativa and T6 were highly positively correlated, which suggests no competition and that infection with one species does not preclude infection by the other species. Our study demonstrates low host specificity and minimal interspecific competition among Trichinella larvae within muscles of naturally co-infected carnivore hosts.