West Nile virus associations in wild mammals: a synthesis

Abstract

Exposures to West Nile virus (WNV) have been documented in a variety of wild mammals in both the New and Old Worlds. This review tabulates at least 100 mammal species with evidence of WNV exposure. Many of these exposures were detected in free-ranging mammals, while several were noted in captive individuals. In addition to exposures, this review discusses experimental infections in terms of the potential for reservoir competence of select wild mammal species. Overall, few experimental infections have been conducted on wild mammals. As such, the role of most wild mammals as potential amplifying hosts for WNV is, to date, uncertain. In most instances, experimental infections of wild mammals with WNV have resulted in no or low-level viremia. Some recent studies have indicated that certain species of tree squirrels (Sciurus spp.), eastern chipmunks (Tamias striatus), and eastern cottontail rabbits (Sylvilagus floridanus) develop viremia sufficient for infecting some mosquito species. Certain mammalian species, such as tree squirrels, mesopredators, and deer have been suggested as useful species for WNV surveillance. In this review article, the information pertaining to wild mammal associations with WNV is synthesized.

Vector-Virus Interactions and Transmission Dynamics of West Nile Virus

“…, will transmit virus. These studies are well summarized elsewhere and therefore will not be discussed further [141]. …”

Cerebrospinal Fluid Biomarker Candidates Associated with Human WNV Neuroinvasive Disease

“…In nature, avian hosts are the main reservoir of WNV; nevertheless transmission to other vertebrates can occur [2]. Humans and equines are sensitive to WNV infection, but they are considered as incidental dead-end hosts, due to the low and short viremia [3].While the majority of humans infected with WNV remain asymptomatic, approximately 20% develop a transient febrile illness, known as West Nile fever (WNF); and about 1% of infected individuals develop a neuroinvasive disease (WNND) characterized by encephalitis, meningitis, and/or acute flaccid paralysis, leading in some cases to a fatal outcome [4], [5].…”

Are tree squirrels involved in the circulation of flaviviruses in Italy?

“…WNV and USUV belong to the mosquito-borne flavivirus group and are generally maintained in an enzootic life cycle involving ornithophilic mosquitoes (mostly genus Culex) as competent vectors and wild birds as main reservoir hosts. Even though mammals are susceptible to infection by these flaviviruses, most species are considered incidental or dead-end hosts, as they typically show a short-term and low-level viremia that prevents transmission to competent vectors (Root, 2013). TBEV is the most relevant zoonotic virus within the tick-borne flavivirus group in Europe.…”