Challenges to controlling rabies in skunk populations using oral rabies vaccination: A review.

Controlling rabies in skunk populations is an important public health concern in many parts of the United States due to the potential for skunk rabies outbreaks in urban centres and the possible role for skunks in raccoon rabies variant circulation. Oral rabies vaccination (ORV) programmes have supported wildlife rabies control efforts globally but using ORV to control rabies in skunk populations has proven more challenging than with other target species, like foxes, coyotes and raccoons. A review of published studies found that some ORV constructs are immunogenic in skunks and protect against virulent rabies virus challenges, especially when delivered by direct installation into the oral cavity. However, in field ORV programmes using currently available vaccine-bait formats and distribution methods targeting other rabies reservoir species, skunks often fail to seroconvert. Field effectiveness of ORV in skunks appears to be limited by poor bait uptake or inadequate ingestion of vaccine rather than from poor vaccine efficacy. Observations of captive skunks revealed vaccine spillage when handling and biting into baits such that modification of bait formats might improve field effectiveness. In addition, a dose-response relationship between bait distribution density and post-baiting seroconversion among skunks was observed across the limited number of field studies. Additional research is needed to identify opportunities to modify ORV baits and distribution strategies to improve the viability of ORV as a rabies control strategy in skunks.