Concerned that raccoon rabies could infect wildlife and humans, Canadian authorities are reaching across the border to help support oral vaccination programs in Northeastern states by veterinarians and wildlife biologists from the Cornell University College of Veterinary Medicine.
Now, the province of Quebec is joining Ontario to assist programs that distribute vaccine-filled baits for raccoons in northern counties of New York, Vermont, New Hampshire and Maine.
"Our Canadian colleagues have been struggling to control fox rabies, and they have demonstrated success with oral vaccines in baits," said Laura Bigler, Ph.D., leader of the raccoon rabies vaccination programs in the college's Veterinary Diagnostic Laboratory. "The last thing they need now is for raccoon rabies to spread to those provinces."
But raccoon rabies has progressed northward in the northeast United States at the rate of about 25 miles a year. International borders mean nothing to wandering animals, not even borders separated by rivers, which freeze in winter or can be bridged by stow-away raccoons. So the Cornell program attempts to immunize susceptible populations of raccoons, beginning with areas along the U.S.-Canada border.
To date, support for the raccoon vaccination efforts has come from government agencies where the greatest local threat was perceived -- from some counties in northern New York, from the New York State Department of Health and from funds allocated by members of the New York State Legislature. In 1995, Ontario began providing scientific assistance, personnel and aircraft to drop vaccine baits in New York counties in the Niagara and St. Lawrence river areas. Besides its continuing in-kind assistance, Ontario contributed $125,000 to the Cornell-based vaccine program in 1996.
Financial assistance from Quebec in 1997 will allow the raccoon vaccination program to expand strategically to border regions of northern New York and Vermont, according to Donald Lein, D.V.M., Ph.D., director of the Veterinary Diagnostic Laboratory at Cornell. However, a truly regional approach -- treating raccoon rabies in New England and the Northeast and including Ohio, Pennsylvania and Virginia -- awaits federal, state and local support, he noted.
"In one sense, this is still an experiment," said Bigler, who in January traveled to Texas to aid that state's rabies vaccination program for coyotes and grey foxes. "We are still collecting data in New York to evaluate types of baits and the best distribution strategies and densities, to further improve the cost-effectiveness and efficacy of these programs." The vaccination program in New York's Niagara County last year, for example, showed that as few as 50 vaccine baits per square kilometer are enough to reach a significant percentage of raccoons, she said. Some previous programs had used more baits, which are distributed from specially equipped helicopters or from vehicles on the ground.
Explaining why Canada is spending money to treat American wildlife, Bigler said that raccoon rabies is considered to be a greater threat to human health than fox rabies because the more numerous raccoons live in closer association with humans. The annual cost of post-exposure treatment for people who are exposed to the deadly disease from animals far exceeds expenditures for preventive immunization of wildlife.
"Canada sees working with us as a better investment than waiting for raccoon rabies to walk across the border," Bigler said. "We have shown that we can stop raccoon rabies at the border and even move the vaccinated disease-free zone southward. Our St. Lawrence barrier has already moved south since the first application in 1995."
Oral vaccine programs in New York and elsewhere, including Massachusetts' Cape Cod, are demonstrating the potential for the strategy, Lein said, predicting: "We can put a noose around raccoon rabies and eliminate this disease from the Northeast once and for all."