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During late summer and early autumn, raccoons in Vermont and New Hampshire witness something of a miracle: food falls from the sky. This is not their traditional fare of plants and invertebrates but rather an appetizing edible packet filled with VR-G, an oral rabies vaccine. As the raccoons devour this heaven-sent meal, they are vaccinated against rabies, an increasing problem in the two states.
Rabies was first identified in the region in 1992, when a fox in Vermont and a raccoon in New Hampshire were found with the disease. Though raccoons have served as a rabies reservoir in the southeastern U.S. since the 1950s, it wasn’t until a mid-Atlantic outbreak in the 1970s that rabies spread north across New England and New York. In 2005, there were 59 reported cases of rabies in wild animals in Vermont, up from 44 in 2004. Cases are reported year round, with the number rising through the late spring and summer as animals travel longer distances and intermingle in the warmer months.
In 1997, in response to the growing number of cases in the Northeast, Cornell University’s College of Veterinary Medicine partnered with authorities in Ontario, Quebec, and U.S. state agencies in an attempt to stop the spread of rabies across the international border. Rabies prevention is much cheaper than rabies treatment. Estimated to exceed $3 million annually, treatment costs include the vaccination of pets, animal control programs, rabies laboratory work, and post-exposure medical treatment for pets and humans. Dropping bait is more cost-effective than controlling rabies through these pre- and post-exposure means since each bait costs between $1 and $1.50.
During a bait drop, an airplane flies a predetermined pattern using GIS (geographical information system) lines and waypoints, dropping bait at fixed intervals over diseased areas. The plane flies at an altitude of 500 feet, and while the pilot makes sure to follow course, the co-pilot controls where the bait is dropped, assuring that it doesn’t land in roads or catch a family barbeque unaware. In urban areas, the bait packets are placed by hand.
A plane can drop from 15,000 to 30,000 bait packets during a three-hour flight. Each year since 1997, sometime during summer or autumn, New Hampshire and Vermont raccoons have been treated to supper from the sky. In 2005, 342,462 bait packets were dropped in Vermont and 28,037 in New Hampshire.
There are two types of bait to tempt the raccoons. The hand-placed bait is a 1 ¼-inch square pellet made from fishmeal. It is open on both ends, with the vaccine tucked into the center. The ¾- x 2-inch aerial bait, dropped from a plane, consists of a packet covered with an oily coating and filled with the vaccine. Both types of bait are imprinted with a toll-free number to call for information. These bait packets are not harmful to people or pets but should be left undisturbed if found. Ingesting bait will not substitute for vaccination for your pet. They may suffer from an upset stomach but will still have to receive the shot at your veterinarian’s office.
After a bait drop, researchers monitor the raccoons in the area. State biologists set live traps for the animals, and once they have a captive, they take a sample of the animal’s blood and send it to a lab to be tested for vaccination. Only those raccoons that were lucky enough to find the free meal end up being vaccinated. The examined raccoons are then released.
How effective are these fast-food dinners in preventing the spread of rabies? The jury is still out. Bait drops were first used in 1990, and the number has now risen to over 1,000,000 bait packets distributed annually across the eastern United States. Over that time, researchers have tested the bait packets to be sure they are not harming non-target species and are being ingested, but there is still much that is unknown. Currently, studies are evaluating vaccination rates in target species, effects on non-target populations, alternative vaccines, and alternative distribution patterns.
Bait drops are a potentially reliable and cost-effective way to prevent the spread of rabies, but they don’t supersede old-fashioned precaution. Any mammal can contract rabies and spread it to others through infected saliva. The most common reservoirs of rabies in the wild are raccoons, skunks, coyotes, and bats. Most human cases are traced back to the bite of an infected animal acting suspiciously, either biting vigorously at anything or acting sick or overly tame. View all wildlife from a distance, keep your pets vaccinated, and if you think you, your pet, or someone else has had contact with an infected animal, contact state officials as soon as possible. With your help, and the raccoon’s meals from the sky, perhaps rabies will start to loosen its grip on New Hampshire and Vermont.