Abstract

The black-footed ferret (Mustela nigripes) is a highly endangered species that has been reintroduced into several sites in South Dakota. Veterinarians have played an important role in establishing a preventive health program for the free-ranging South Dakota black-footed ferret population and in the development of reproductive techniques for use in the captive breeding program. Routine veterinary care of free-ranging black-footed ferrets in South Dakota happens twice each year. Each fall, starting in 1997, as many of the young kits and adults of the roughly three hundred ferrets in the Conata Basin area are captured. The kits and adults without a microchip are sedated with isoflurane gas (IsoFlo, Abbott Laboratories, Abbott Park, IL) and oxygen. While they are sedated, they are vaccinated for canine distemper with a commercial, recombinant vaccine (Purevax Ferret Distemper, Merial Limited, Duluth, GA), vaccinated with a recombinant F1-V fusion protein plague vaccine (Dr. Tonie Rocke, U.S. Geological Survey, National Wildlife Health Center, Madison, WI), implanted with an AVID microchip (AVID Identification Systems, Inc., Norco, CA), and topically treated with Frontline spray (0.29% fipronil, Merial Limited, Duluth, GA) for flea and tick control. Adults that already have a microchip receive a booster of the distemper vaccine and plague vaccine without any sedation. In the spring adult males are captured for semen collection. The semen is cryopreserved and used in the captive breeding program.

Infectious disease outbreaks have wiped out entire populations of black-footed ferrets. Sylvatic plague (Yersinia pestis) is one of these devastating diseases and it threatens the long-term survival of the black-footed ferret throughout its entire range. In May of 2008, plague was discovered in the Conata Basin recovery site in the Buffalo Gap National Grassland. Federal agencies decided to dust the prairie dog colonies in an attempt to reduce fleas and limit the outbreak. Roughly eleven thousand acres were treated with DeltaDust (0.05% deltamethrin, Bayer Environmental Science, Montvale, NJ). In addition, the black-footed ferrets in the area were captured and vaccinated with the recombinant F1-V plague vaccine and topically treated with Frontline spray. Two hundred and sixteen black-footed ferrets were vaccinated between June and November. Despite this labor intensive effort, roughly fifty to sixty black-footed ferrets succumbed to plague in 2008. Overall, this number represented approximately 20% of the ferret population in this site, and thus, the vaccination and flea reduction program was considered very successful as plaque epizootics can have up to 100% mortality.