Wildlife Services (WS) -- a program within the U.S Department of Agriculture's (USDA) Animal and Plant Health Inspection Service -- works to limit the spread of rabies natiowide as part of its mission to minimize wildlife damage to agricultural, urban, and natural resources. An important part of WS' mission includes cooperating in wildlife disease-management efforts in order to protect public health and safety.
WS established its National Rabies Management Program in recognition of the changing scope of rabies. The program aims to prevent the further spread of rabies by containing the raccoon variant and, eventually, to eliminate terrestrial rabies in the United States through an integrated program involving the use of oral rabies vaccination (ORV) of wildlife.
Raccoons are one of the most recognizable wildlife species. Whether you have seen raccoons on television or in your backyard, rummaging through a trashcan, they are easily identified by their black face mask and ringed tail. Although you may view them as cute and cuddly, raccoons are one of the species most often responsible for transmitting rabies and should be left alone.
Rabies is caused by a virus that affects the central nervous system in mammals and is almost always transmitted through saliva when an infected animal bites an uninfected animal or person. Untreated, rabies is always fatal; however, effective vaccines are available to protect people and pets.
According to the Deparment of Health and Human Services' Center for Disease Control and Prevention, more than 90 percent of rabies cases reported in the United States each year are found in wildlife. Several different variants of the rabies virus exist in this country. Each variant is spread predominantly by one wildlife species, but all variants are capable of infecting warm-blooded mammals, including humans. Raccoons and skunks account for the most reported cases, but bats, foxes, and coyotes are also among the most commonly infected wildlife species.
The cost of living with rabies in America is high and growing,exceeding $300 million per year. Although rabies vaccinations have been available for domestic animals for many years, until recently no such preventive measure existed to control rabies in wildlife.
Since 1995, WS has been working cooperatively with local, State, and Federal governments, universities, and other partners to address the public health problem by distributing ORV baits in targeted areas. While raccoon vaccination is the largest of WS' efforts, the program has been involved in a cooperative ORV program in Texas that targets canine rabies in coyotes and a unique variant of the disease in gray foxes. Scientists at WS' National Wildlife Research Center (NWRC) are conducting research in Arizona to learn more about the use of ORV in skunks and feral dogs.
At this time, the raccoon rabies variant is found only in the Eastern United States. A vaccination zone has been established stretching from Maine to Alabama to prevent the westward spread of the virus that causes raccoon rabies.
Annually, WS and cooperators distribute about 6.5 million baits in selected states to create a zone where raccoon rabies can be contained. In setting up that zone, WS wildlife biologists made sure to incorporate features of the natural landscape that can help the containment effort (mountain ranges and large bodies of water that can act as natural barriers). For instance, the densely forested habitats at high elevations of the Appalachian Mountains limit raccoon movements and help slow the spread of raccoon rabies virus west of this mountain range.
In 2006, the program shifted the Appalachian Ridge ORV zone 5 miles to the east, an important step toward the longrange goal of eliminating raccoon rabies. The goal is to continue shifting the zone eastward until raccoon rabies has been eliminated all the way to the east coast.
Raccoon movements in the Northeastern United States are a concern as well. Since the year 2000, cooperative efforts between the United States and Canada have maintained a zone to contain raccoon rabies within its present boundaries. The northeastern part of WS' program includes New York, Vermont, New Hampshire, and Maine. Baits are distributed along the border to prevent the northward spread of raccoon rabies into Canada.
DISTRIBUTING THE VACCINE
The ORV baits, developed and manufactured by Merial, Inc., in Athens, GA, consist of a sachet, or plastic packet, containing Raboral V-RG rabies vaccine. To make the baits attractive, the sachets containing vaccine are sprinkled with fishmeal coating or encased inside hard fishmeal-polymer blocks about the size of a matchbox. As other private companies work to develop and license effective vaccines, WS may integrate these baits into the program as well.
When a raccoon finds a bait and bites into it, the sachet ruptures, allowing the animal to swallow the vaccine. Raccoons that swallow an adequate dose of the vaccine develop immunity to rabies. As the proportion of the vaccinated animals in the population increases, they act as a buffer to stop the spread of the disease to the other wildlife, domestic animals, and people.
Field crews distribute ORV baits by air or ground baiting. Fixed-wing aircraft are the most effective means for distributing large numbers of the ORV baits. Hand baiting is important for reaching urban areas, where there may be safety risks associated with distributing baits from planes, and for lessening the likelihood that people or domestic animals will contact the baits.
WHAT TO DO IF YOU FIND ONE OF THE BAITS
If you come across a bait, you should leav it where you found it. Do not attempt to remove a bait from your pet's mouth; doing so may cause you to be bitten. Raboral V-RG is safe for more than 60 species, including domestic dogs and cats. The vaccine does not contain the live rabies virus.
If you come in contact with the pink liquid vaccine, wash the affected area thoroughly with soap and water and call the U.S. Department of Agriculture's Wildlife Services office at 866-4-USDA-WS (866-487-3297) for further information and referral.
Information provided y the United States Department of Agriculture