New geographic records for Echinococcus canadensis in coyotes and moose from Nova Scotia, Canada

Abstract

Echinococcus spp. tapeworms can cause serious diseases in mammals, including humans. Within the E. granulosus species complex, metacestodes produce unilocular cysts that are responsible for cystic echinococcosis in animal intermediate hosts. Canids are definitive hosts, harbouring adult cestodes in their intestines. Adult E. canadensis were recovered from the small intestine of 1 of 262 coyotes ( Canis latrans ) from Nova Scotia, Canada. Subsequently, we found unilocular cysts in lungs and livers of 4 of 8 sympatric moose ( Alces alces ) from Cape Breton Island. DNA was extracted from three cysts using the Qiagen DNeasy Blood and Tissue kit and assayed by polymerase chain reaction (PCR) with primers (cest4 and cest5) for a 117-bp region of the small subunit of ribosomal RNA of E. granulosus sensu lato , and further validated as E. canadensis G8 using primers targeting nicotinamide adenosine dinucleotide dehydrogenase subunit 1 (ND1) and cytochrome c oxidase subunit 1 (CO1) mitochondrial genes. These are the first records of E. canadensis in any of the three Maritime provinces, which include Nova Scotia, New Brunswick, and Prince Edward Island. The parasite was thought to be absent in this region due to extirpation of wolves ( Canis spp.) in the 1800s. These findings suggest that further wildlife surveillance and risk assessment is warranted.

Zoonotic helminths – why the challenge remains

“…A domestic cycle of transmission involving domestic dogs and farmed elk was also identified in western Canada (Thompson, 2013). Recent reports of E. canadensis in coyotes in Canada suggest the emergence of this species in new endemic regions (Santa et al , 2018; Priest et al , 2021) and given that, the urbanization of the coyote in Canada is of potential public health significance.…”

New Geographic Records for Trichinella nativa and Echinococcus canadensis in Coyotes (Canis latrans) from Insular Newfoundland, Canada

“…Dog owners in Newfoundland should be aware of this risk and avoid feeding uncooked meat or organs from hunted cervids to their dogs, as well as consult their veterinarian regarding regular deworming of dogs to protect human health. Hydatid cysts in the lungs or livers of moose and caribou pose no food safety risk to people, but if consumed by dogs or wild canids they can develop into adult tapeworms and pass eggs in feces that are immediately infective to people (Priest et al 2021).…”

“…Within Canada, insular Newfoundland, Nova Scotia, New Brunswick, and Prince Edward Island have previously been considered free of E. canadensis due to the absence of wolves ( Canis lupus ) as definitive hosts (Schurer et al 2013), but over the last decade there have been reports and genetic evidence of Labrador wolves ( Canis lupus labradorius ) in insular Newfoundland (Callahan, unpublished data). Recently E. canadensis was documented in moose from Nova Scotia (Priest et al 2021) and a hydatid cyst, the form seen in intermediate hosts, was found in the lung of a moose harvested in 2018 from Gros Morne National Park, insular Newfoundland (Pollock, provincial veterinarian, pers. comm.).…”

“…The introduction to and establishment of parasites in new and isolated geographic regions are dependent upon three primary factors: 1) ease and frequency of movement of hosts between enzootic and nonenzootic regions, 2) presence and density of suitable hosts, and 3) suitable climate and microhabitat for parasite survival and transmission (Priest et al 2021; Santa et al 2021). In 2012, Labrador wolves were documented on insular Newfoundland for the first time since their extirpation in the 1930s (Callahan, pers.…”

Exploring the genetic diversity of genotypes G8 and G10 of the Echinococcus canadensis cluster in Europe based on complete mitochondrial genomes (13 550–13 552 bp)

“…parasite tissue are laborious tasks (Moks et al, 2008;Schurer et al, 2013;Romig et al, 2017). However, by analyzing selected mt loci, predominantly cox1 and/or nad1 gene fragments, available studies have provided valuable first insight into the genetic variation of these genotypes (e.g., Lavikainen et al, 2006;Moks et al, 2008;Nakao et al, 2013;Schurer et al, 2013;Yang et al, 2015;Dell et al, 2020;Priest et al, 2021). For example, such studies have indicated that the extent of genetic variation within the two E. canadensis genotypes (G8 and G10) is considerably lower and less complex than within other Echinococcus species or genotypes, such as E. granulosus sensu stricto (s.s., G1/G3) and G6/G7 of the E. canadensis cluster (Romig et al, 2015;Kinkar et al, 2018a, b;Laurimäe et al, 2018b).…”