Zoonotic Echinococcus spp. cestodes (E. canadensis and E. multilocularis) infect domestic animals, wildlife, and people in regions of Canada and the USA. We recovered and quantified Echinococcus spp. cestodes from 22 of 307 intestinal tracts of wild canids (23 wolves, 100 coyotes, 184 red and arctic foxes) in the state of Maine and the province of Québec. We identified the species and genotypes of three Echinococcus spp. cestodes per infected animal by sequencing mitochondrial DNA at two loci. We further confirmed the absence of E. multilocularis by extracting DNA from pools of all cestodes from each animal and running a duplex PCR capable of distinguishing the two species. We detected E. canadensis (G8 and G10), but not E. multilocularis, which is emerging as an important human and animal health concern in adjacent regions. Prevalence and median intensity of E. canadensis was higher in wolves (35%, 460) than coyotes (14%, 358). This parasite has historically been absent in Atlantic regions of North America, where suitable intermediate hosts, but not wolves, are present. Our study suggests that coyotes are serving as sylvatic definitive hosts for E. canadensis in Atlantic regions, and this may facilitate eastward range expansion of E. canadensis in the USA and Canada. As well, compared to wolves, coyotes are more likely to contaminate urban green spaces and peri-urban environments with zoonotic parasites.
The blacklegged tick,
Ixodes scapularis
, is the primary vector of multiple human pathogens, including the causative agents of Lyme disease, anaplasmosis, and babesiosis. Both
I. scapularis
and its associated pathogens have expanded their geographic range throughout the northeastern Unites States and into northern New England. Through this study, we present an updated distribution of
I. scapularis
in Maine and report the first statewide passive surveillance infection and coinfection prevalence of
Borrelia burgdorferi
,
Anaplasma phagocytophilum
, and
Babesia microti
within the state's
I. scapularis
population. In 2019, we collected 2016 ticks through a passive surveillance program, in which Maine residents submitted tick samples for identification and/or pathogen testing. We used a single multiplex quantitative PCR assay to detect tickborne pathogens in 1901 tick samples. At the state level, we found that
Bo. burgdorferi
and
A. phagocytophilum
infection rates of adults (42.4%, 11.1%) were nearly double that of nymphs (26.9%, 6.7%), whereas
B. microti
prevalence was similar for both adults (6.5%) and nymphs (5.2%). Spatially, we found an uneven distribution of both tick activity and pathogen prevalence, with both increasing on a north to south gradient. We also noted a potential association between the ratio of adult to nymphal ticks and the incidence of tickborne disease in human populations, with counties that exhibit high rates of human disease also maintaining low adult to nymph ratios.
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