Serological Responses of Raccoons and Striped Skunks to Ontario Rabies Vaccine Bait in West Virginia during 2012-2016.

Shylo R Johnson,Samual A Mills,Richard B Chipman,Amy T Gilbert,John T Forbes,Amy J Davis,Kathleen M Nelson,Kurt C Vercauteren,Dennis Slate

doi:10.3390/v13020157

Shylo R Johnson, Samual A Mills + Show 7 more

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https://doi.org/10.3390/v13020157

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Abstract

Since the 1990s, oral rabies vaccination (ORV) has been used successfully to halt the westward spread of the raccoon rabies virus (RV) variant from the eastern continental USA. Elimination of raccoon RV from the eastern USA has proven challenging across targeted raccoon (Procyon lotor) and striped skunk (Mephitis mephitis) populations impacted by raccoon RV. Field trial evaluations of the Ontario Rabies Vaccine Bait (ONRAB) were initiated to expand ORV products available to meet the rabies management goal of raccoon RV elimination. This study describes the continuation of a 2011 trial in West Virginia. Our objective was to evaluate raccoon and skunk response to ORV occurring in West Virginia for an additional two years (2012–2013) at 75 baits/km2 followed by three years (2014–2016) of evaluation at 300 baits/km2. We measured the change in rabies virus-neutralizing antibody (RVNA) seroprevalence in targeted wildlife populations by comparing levels pre- and post-ORV during each year of study. The increase in bait density from 75/km2 to 300/km2 corresponded to an increase in average post-ORV seroprevalence for raccoon and skunk populations. Raccoon population RVNA levels increased from 53% (300/565, 95% CI: 50–57%) to 82.0% (596/727, 95% CI: 79–85%) during this study, and skunk population RVNA levels increased from 11% (8/72, 95% CI: 6–20%) to 39% (51/130, 95% CI: 31–48%). The RVNA seroprevalence pre-ORV demonstrated an increasing trend across study years for both bait densities and species, indicating that multiple years of ORV may be necessary to achieve and maintain RVNA seroprevalence in target wildlife populations for the control and elimination of raccoon RV in the eastern USA.

Highlights

Oral rabies vaccination (ORV) is a proven prevention and control method for largescale landscape applications targeting rabies viruses (RV) circulating in wildlife [1]
We investigated the interaction between baiting duration and sampling period, to account for trends over time pre-oral rabies vaccination (ORV) compared to post-ORV
We processed sera for rabies virus-neutralizing antibody (RVNA) from 3256 carnivores sampled during the period 2012–2016

Summary

Introduction

Oral rabies vaccination (ORV) is a proven prevention and control method for largescale landscape applications targeting rabies viruses (RV) circulating in wildlife [1]. ORV has been successfully used to eliminate the canine RV variant in coyotes (Canis latrans) in south Texas, USA [2,3] and RV in red foxes (Vulpes vulpes) and raccoon dogs (Nyctereutes procyonoides) across Europe [4]. The use of ORV targeting red foxes and striped skunks (Mephitis mephitis) eliminated the arctic fox (Vulpes lagopus) RV from large areas in southern. Related viruses have re-emerged in red foxes and striped skunks in southwestern Ontario, requiring new management activities for arctic fox RV control [7]. Strategies focused on ORV have proven effective across species and geographic areas and have prevented the westward spread of raccoon RV from the eastern USA. Strategies focused on ORV have proven effective across species and geographic areas and have prevented the westward spread of raccoon RV from the eastern USA. 4.0/).

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