Tick-borne zoonotic flaviviruses andBorreliainfections in wildlife hosts: what have field studies contributed?

Abstract

Tick-borne flaviviruses andBorreliaspp. are globally spread pathogens of zoonotic potential which are maintained by a transmission cycle at the interface between ticks and vertebrate hosts, mainly wild animals. We reviewed how those infections have been studied in wildlife species in the field to discuss how collected data provided relevant epidemiological information and identify needs for further studies. The literature was screened for populational studies on direct or antibody detection for tick-borneBorreliaspp. and flaviviruses in animals, in the wild. Overall,Borreliaspp. were more studied (73% of case studies, representing 297 host species) than flaviviruses (27% of case studies, representing 114 host species). Studies on bothBorreliaspp. and flaviviruses focused mainly on the same species (namely bank vole and yellow-necked mouse). Species with potential to act as reservoir hosts were overlooked, notably passerine birds. Most studies were order-specific and cross-sectional. We highlight the necessity of collecting both demographics and infection data in wildlife studies, and to consider communities of species, to better estimate zoonotic risk potential.