title: Capillaria hepatica in wild Norway rats (Rattus norvegicus) from Vancouver, Canada.
abstract: Capillaria hepatica is a parasitic nematode that infects the liver of rats (Rattus spp.), and occasionally other mammalian species, including humans. Despite its broad geographic distribution and host range, the ecology of this parasite remains poorly understood. We characterized the ecology of C. hepatica in urban Norway rats (Rattus norvegicus) in Vancouver, Canada. The overall prevalence of C. hepatica among Norway rats was 36% (241/671); however, there was significant variation in prevalence among city blocks. Using a generalized linear mixed model to control for clustering by block (where OR is odds ratio and CI is confidence interval), we found C. hepatica infection was negatively associated with season (spring [OR=0.14, 95% CI=0.05-0.39]; summer [OR=0.14, 95% CI=0.03-0.61]; winter [OR=0.34, 95% CI=0.13-0.84], compared to fall) and positively associated with sexual maturity (OR: 7.29, 95% CI=3.98-13.36) and presence of cutaneous bite wounds (OR=1.87, 95% CI=1.11-3.16). Our understanding of the ecology of C. hepatica in rats is hindered by a paucity of data regarding the main mechanisms of transmission (e.g., environmental exposure vs. active cannibalism). However, associations among infection, season, maturity, and bite wounds could suggest that social interactions, possibly including cannibalism, may be important in transmission.
authors.affiliation: 1  Department of Veterinary Pathology, Western College of Veterinary Medicine, University of Saskatchewan, 52 Campus Drive, Saskatoon, Saskatchewan S7N 5B4, Canada.
authors.forename: Jamie L
authors.initials: JL
authors.lastname: Rothenburger
authors.forename: Chelsea G
authors.initials: CG
authors.lastname: Himsworth
authors.forename: Victoria
authors.initials: V
authors.lastname: Chang
authors.forename: Manigandan
authors.initials: M
authors.lastname: LeJeune
authors.forename: Frederick A
authors.initials: FA
authors.lastname: Leighton
mesh_terms: D000818:Animals; D000835:Animals, Wild; D002170:Canada / Q000453:epidemiology; D002195:Capillaria / Q000302:isolation & purification*; D017189:Enoplida Infections / Q000453:epidemiology / Q000469:parasitology / Q000662:veterinary*; D005260:Female; D008099:Liver / Q000469:parasitology / Q000473:pathology; D008297:Male; D051381:Rats; D012376:Rodent Diseases / Q000453:epidemiology / Q000469:parasitology*
keywords: Black rat; Calodium hepaticum; Capillaria hepatica; Norway rat; Rattus; ecology; urban