National Wildlife Research Center (NWRC)

Dog overpopulation is a serious problem in many parts of the world. Each year millions of dogs are euthanized because their owners do not want them, they are born feral or because stray dogs pose a potential public health risk, primarily due to bite injuries and the spread of rabies. Capturing and euthanizing overabundant dogs to control the spread of diseases, such as rabies, is unpopular. Instead, rabies vaccination programs for dogs are often used to reduce human rabies cases and have been successful in North America, Europe, South America, Asia and Africa. Often, rabies vaccination programs involve not only the vaccination of animals, but also surgical sterilization to help reduce local populations. Recently, the management of stray dogs has focused on surgical sterilization through a system of “catch-neuter-release" programs. For example, Moscow officials recently announced a two-year, $64 million program to castrate as many as 50,000 stray dogs in the city.

In an effort to reduce the cost of such programs, Wildlife Services recently proposed the use of GonaCon™, an immunocontraceptive vaccine, as part of the rabies management strategy. Scientists suggest that stray dogs be vaccinated with both the rabies and GonaCon™ vaccines. This would provide a more cost-effective method for reducing stray dog populations which, in turn, would decrease the potential spread of rabies. The estimated cost of the GonaCon™ vaccine for dogs is approximately $1 per dose.

The GonaCon™ vaccine was developed by NWRC scientists in Fort Collins, CO. It can induce multi-year infertility in a variety of mammalian species, including white-tailed deer, feral hogs, wild horses, prairie dogs, bison, and feral cats. It stimulates the production of antibodies that bind to the gonadotropin-releasing hormone (GnRH). GnRH is a hormone the signals the production of sex hormones. By binding to the GnRH, the antibodies reduce GnRH’s ability to stimulate the release of sex hormones, inhibiting sexual activity.

"If we find that GonaCon™ can work in conjunction with the rabies vaccine, this could provide veterinarians, animal control officers, wildlife managers and public health officials with a whole new way to manage stray and feral dog populations," notes NWRC Research Physiologist Dr. Lowell Miller.

NWRC scientists are currently conducting laboratory and field studies to explore whether a combined series of rabies and immunocontraception vaccinations would be an effective strategy for reducing stray dog populations and the occurrence of rabies in developing countries.

For more information, please contact Dr. Lowell Miller at 970-266-6163 or lowell.a.miller@aphis.usda.gov.