Incrimination of shrews as a reservoir for Powassan virus

Heidi K Goethert,Thomas N Mather,Sam R Telford,Richard W Johnson

doi:10.1038/s42003-021-02828-1

Heidi K Goethert, Thomas N Mather + Show 2 more

Open Access

https://doi.org/10.1038/s42003-021-02828-1

Copy DOI

Abstract

Powassan virus lineage 2 (deer tick virus) is an emergent threat to American public health, causing severe neurologic disease. Its life cycle in nature remains poorly understood. We use a host-specific retrotransposon-targeted real time PCR assay to test the hypothesis that white-footed mice, considered the main eastern U.S. reservoir of the coinfecting agent of Lyme disease, is the reservoir for deer tick virus. Of 20 virus-infected host-seeking nymphal black-legged ticks 65% fed on shrews and none on mice. The proportion of ticks feeding on shrews at a site is positively associated with prevalence of viral infection, but not the Lyme disease agent. Viral RNA is detected in the brain of one shrew. We conclude that shrews are a likely reservoir host for deer tick virus and that host bloodmeal analysis can provide direct evidence to incriminate reservoir hosts, thereby promoting our understanding of the ecology of tick-borne infections.

Highlights

Powassan virus lineage 2 is an emergent threat to American public health, causing severe neurologic disease
There are two distinct Powassan virus lineages: lineage 1, which is found in North America and far Eastern Asia, and lineage 2 which has only been found in North America[1]
Before 20092, all tick-borne encephalitis cases in North America have been attributed to POWV, because etiology has usually been described by the presence of specific antibody and the two viruses are serologically indistinguishable[3]

Summary

Introduction

Powassan virus lineage 2 (deer tick virus) is an emergent threat to American public health, causing severe neurologic disease. We report incrimination of a likely vertebrate reservoir of DTV by analyzing hostseeking infected nymphal ticks for evidence of the identity of the host providing the infectious bloodmeal in the preceding larval stage.

Results

Conclusion