An invasive mammal (the gray squirrel, sciurus carolinensis) commonly hosts diverse and atypical genotypes of the zoonotic pathogen borrelia burgdorferi Sensu Lato

Millins, C; Magierecka, A; Gilbert, L; Edoff, A; Brereton, A; Kilbride, E; Denwood, M; Birtles, RJ; Biek, R

Abstract

Invasive vertebrate species can act as hosts for endemic pathogens and may alter pathogen community composition and dynamics.
For the zoonotic pathogen Borrelia burgdorferi sensu lato, the agent of Lyme borreliosis, recent work shows invasive rodent
species can be of high epidemiological importance and may support host-specific strains. This study examined the role of gray
squirrels (Sciurus carolinensis) (n � 679), an invasive species in the United Kingdom, as B. burgdorferi sensu lato hosts. We
found that gray squirrels were frequently infested with Ixodes ricinus, the main vector of B. burgdorferi sensu lato in the United
Kingdom, and 11.9% were infected with B. burgdorferi sensu lato. All four genospecies that occur in the United Kingdom were
detected in gray squirrels, and unexpectedly, the bird-associated genospecies Borrelia garinii was most common. The second
most frequent infection was with Borrelia afzelii. Genotyping of B. garinii and B. afzelii produced no evidence for strains associated
with gray squirrels. Generalized linear mixed models (GLMM) identified tick infestation and date of capture as significant
factors associated with B. burgdorferi sensu lato infection in gray squirrels, with infection elevated in early summer in squirrels
infested with ticks. Invasive gray squirrels appear to become infected with locally circulating strains of B. burgdorferi sensu lato,
and further studies are required to determine their role in community disease dynamics. Our findings highlight the fact that the
role of introduced host species in B. burgdorferi sensu lato epidemiology can be highly variable and thus difficult to predict.

• Journal Article Type: Article
• Acceptance Date: Apr 3, 2015
• Online Publication Date: Jun 4, 2015
• Publication Date: Apr 17, 2015
• Deposit Date: Mar 22, 2016
• Publicly Available Date: Apr 5, 2016
• Journal: Applied and Environmental Microbiology
• Print ISSN: 0099-2240
• Electronic ISSN: 1098-5336
• Publisher: American Society for Microbiology
• Volume: 81
• Issue: 13
• Pages: 4236-4245
• DOI: https://doi.org/10.1128/AEM.00109-15
• Publisher URL: http://dx.doi.org/10.1128/AEM.00109-15
• Related Public URLs: http://aem.asm.org/
• Additional Information: Funders : Biotechnology and Biosciences Sciences Research Council (BBSRC);Glasgow Natural History Society, Blodwen Lloyd Binns Bequest Fund; Grant Number: BB/F016786/1