The majority of rabies cases reported to the Centers for Disease Control each year occur in wildlife including skunks, raccoons, bats, foxes, and coyotes. Currently, oral rabies vaccination campaigns are employed to immunize coyotes, foxes, and raccoons. Though skunks are vectors of 6 rabies strains, there is currently no effective oral vaccine or delivery system for skunks. More information is needed to determine if baits currently used are sufficiently attractive to skunks, or if the baits are difficult for skunks to handle and consume. We observed bait manipulation by skunks in penned feeding trials to determine the bait type most conducive to ingestion and delivery of a mock vaccine to skunks. Smaller baits were easier for skunks to manipulate and consume, and vaccine containers coated with bait facilitated sachet puncture and increased the potential for vaccine delivery. Our information will be useful in the development of baits and vaccine containers for large-scale rabies vaccination campaigns that target skunks.

Aerial delivery of rabies vaccine-laden bait is effective and efficient for large-scale vaccination of wildlife. Oral rabies vaccine (ORV) contained in a sachet (or blister pack) inside baits that serve as the mode of delivery currently are used for orally immunizing foxes, raccoons, and coyotes. The technique remains in the vaccine-development stage for oral immunization of skunks. Since skunks are a major vector of the rabies virus, concurrent development of a bait that is sufficiently attractive to skunks would facilitate an immediate mode of delivery once a vaccine is developed. We ran a palatability experiment with different shapes and flavors of baits to assess uptake by captive skunks. The flavors most preferred were fish and chicken. We also evaluated the fate of the sachet (punctured or not) inside baits, which would assist in assessing the delivery of a vaccine dose. On average, cylindrical-shaped baits had a higher percentage of punctured sachets than did rectangular-shaped baits, and baits with their matrix directly coated onto the sachet had a higher percentage of punctured sachets than did those baits in which the sachet was “held.” We also used sulfadimethoxine, a short-term quantifiable biomarker, as a mock vaccine inside sachets in an attempt to quantify the amount of liquid ingested by skunks after consuming baits of different shape and size. While this information could have been useful for assessing the amount of vaccine delivered via sachet puncture, it could not be determined due to an aversive tasting biomarker. For effective ORV bait uptake by skunks, modifications to current baits should include a smaller size and a meat flavor matrix that is directly coated onto the sachet.