Rabies Challenge of Captive Striped Skunks (Mephitis mephitis) following Oral Administration of a Live Vaccinia-Vectored Rabies Vaccine

Abstract

ABSTRACT:Twenty-four adult striped skunks (Mephitis mephitis) were administered the raccoon product formulation of Rabies Vaccine, Live Vaccinia-Vectored (Raboral V-RGH, Merial Limited, Athens, Georgia, USA), either by oral instillation or in vaccine-filled coated sachets either as single or multiple doses. A control group remained unvaccinated. Twentythree of the skunks were challenged 116 days postvaccination with rabies virus (skunk isolate). Six of six naive skunks succumbed to challenge. Four of six skunks that received the vaccine by oral instillation survived challenge. The skunks that did not survive failed to seroconvert following vaccination. None of the skunks that accepted multiple doses of the vaccine offered in coated sachets survived challenge, nor were rabies virus-neutralizing antibodies (VNAs) detected in the sera. Likewise, none of the five skunks ingesting a single sachet developed VNA against rabies. However, in this group one skunk did survive rabies challenge. This preliminary study showed that the vaccinia-vectored oral rabies vaccine Raboral V-RGH, as formulated for use in raccoons, is capable of protecting a percentage of skunks against rabies. However, although the fishmealcoated sachets were readily consumed, subsequent challenge of these animals revealed poor vaccine delivery efficiency.

Community Survey after Rabies Outbreaks, Flagstaff, Arizona, USA

“…During July 21–24, the US Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services, distributed 140,000 oral rabies vaccination (ORV) baits containing a vaccinia–rabies glycoprotein vaccine (Merial, Duluth, GA, USA) by air and ground over a 191-km 2 area in Coconino County, targeting gray foxes (Figure 2). The vaccinia–rabies glycoprotein vaccine is not effective for vaccinating skunks against rabies ( 9 ). A 6-week trap, vaccinate, release campaign targeting skunks was initiated in the eastern portion of Flagstaff at the end of July.…”

ORAL RABIES VACCINATION OF RACCOONS AND STRIPED SKUNKS WITH ONRAB® BAITS: MULTIPLE FACTORS INFLUENCE FIELD IMMUNOGENICITY

“…The low number of skunks observed in proximity of ONRAB baits in field experiments conducted in the Qué bec ORV zone (Boyer et al, 2011) supports that the current bait formulation may not be as attractive for skunks as it is for raccoons. The smaller jaws of skunks may also not permit them to chew the bait in a fashion that is optimal for vaccine delivery, as previously speculated for the V-RG coated-sachet bait (Grosenbaugh et al, 2007). If ONRAB was changed to suit skunks better, bait formulations would still need to remain effective for raccoons.…”

Oral vaccination of raccoons (Procyon lotor) with genetically modified rabies virus vaccines

“…Clearly, additional testing will be required to determine the efficacy of SPBNGAS-GAS in other species. Skunks (such as, M. mephitis) represent another key reservoir species with which the V-RG vaccine has historically demonstrated inconsistent efficacy [18,19]. Further studies to examine the efficacy of SPBNGAS-GAS in skunks are needed to determine if this vaccine could provide protection against rabies in both species.…”