Survey of coyotes, red foxes and wolves from Wyoming, USA, for Echinococcus granulosus s. l.

The paraphyletic group Echinococcus granulosus sensu lato is comprised of parasitic tapeworms of wild and domestic canids such as wolves (Canis lupus) and coyotes (Canis latrans), which serve as definitive hosts, and ungulates, which are the intermediate hosts. Members of this tapeworm group are characterized by both cosmopolitan distribution and zoonotic disease potential. This survey (conducted from 2012 through 2017) was designed to provide insight into the prevalence and distribution of this parasite in wild canids in Wyoming. Echinococcus sp. infections were documented in 14 of 22 gray wolves (63.6%), 1 of 182 coyotes (0.55%) and 0 of 5 red foxes (Vulpes fulva). Echinococcus granulosus s. l. was confirmed in 4 of these 14 specimens obtained from wolves with two parasite specimens corresponding morphologically with E. canadensis (G8/G10). These results suggest that wolves serve as the major definitive host of E. granulosus s. l. in Wyoming, while coyotes do not play an equivalent role. Limited sample size precludes evaluation of the importance of the red fox as a favorable definitive host. Whereas this study documents the occurrence of E. granulosus s. l. in Wyoming, the zoonotic disease risk does not appear to be high. Education remains the key to disease prevention, coupled with good hygienic practices by humans and anthelmintic treatment of domestic dogs exhibiting elevated risk of exposure.