Pre-exposure Prevention Measures
The goals of prevention efforts are to keep people from becoming exposed to rabid animals in the first place, and to prevent disease from developing in those people who do have an exposure to rabies virus. This can be done by:
- reducing encounters between humans and potentially rabid animals;
- immunizing domestic animals;
- providing pre-exposure immunization to people at high risk for being exposed to rabies; and
- giving post-exposure preventive therapy to people who—despite these other efforts—may have been exposed to the virus.
Avoid Wild Animals
Since rabies in this country is primarily a disease of wildlife, an important element of rabies prevention is avoiding wild animals. Many bites and scratches that necessitate post-exposure therapy occur when people try to feed or handle a wild animal. Such activities should be discouraged. Other exposures occur when wild animals are kept as pets. It is illegal to keep skunks, raccoons, coyotes, foxes, or bats as pets in Washington. Furthermore, Washington law prohibits the importation of any such animals into the state (WAC 246-100-191).
Avoid Bats
Bats are the animal most likely to be rabid in Washington. Therefore, avoiding bats is essential to reducing the risk of rabies in humans. Bats should not be picked up or otherwise handled. However, bats play an important role in our ecosystem, and it is neither practical nor desirable to try to eliminate bats from the environment. Rather, effort should be directed at altering the circumstances in which people are exposed to bats.
People commonly encounter bats in their houses. Individual bats occasionally enter buildings accidentally, particularly during the spring and fall as they move between roosts. Young bats sometimes become confused and unintentionally end up indoors—generally in the fall when learning to fly. However, groups of bats may also establish colonies in houses or other buildings. This increases the chances that a person will encounter a bat. Preventing bats from establishing a colony in a building is preferable to trying to exclude them after they become settled, but methods of evicting bats from buildings have been developed.
Screens: In Washington, where many houses do not have screens over windows and doors, the first step to take to reduce the possibility of being exposed to a bat at home is to put up screens.
Vaccinate Domestic Animals
Appropriate vaccination of domestic animals has been central to the marked reduction in human rabies cases that has occurred in the United States.
Approved rabies vaccines are currently available for dogs, cats, ferrets, horses, cattle, and sheep. No vaccine is currently licensed for use in dog-wolf hybrids. Although there are no restrictions on vaccinating dog-wolf hybrids, veterinarians should notify the owners of such animals that if the animal bites a person, it will not be considered vaccinated. In Washington, animal rabies vaccines should only be administered by a licensed veterinarian. Sale of rabies vaccine in any other setting is illegal and should be reported to the Washington State Department of Agriculture at 360.902.1835. While not all localities require that dogs, cats and ferrets be vaccinated, vaccination of these animals should be strongly encouraged.
All licensed animal vaccines available in this country require that a primary dose be given when the animal is at least three months old. All products require a second primary shot one year after the first. Periodic booster doses are necessary for all currently approved animal vaccines. A vaccinated animal must have records documenting primary vaccination and a current booster dose to be considered "fully-vaccinated." For additional details about each vaccine product and dosing schedules, veterinarians should refer to the Compendium of Animal Rabies Prevention and Control which is updated annually by the National Association of State Public Health Veterinarians (and published in the JAVMA).
Pre-exposure Vaccination of Humans
Pre-exposure vaccination should be offered to all persons whose activities place them at increased risk for being exposed to the rabies virus or to potentially rabid animals (such as Washington veterinarians and their staffs,veterinary students, animal control personnel, wildlife rehabilitation workers who have frequent and close contact with bats, laboratory workers doing rabies diagnostic tests, and others who have frequent and close contact with wild animals). In addition, pre-exposure vaccination is recommended for persons who plan to spend substantial time (e.g. one month or more) in countries where dog rabies is common (The Yellow Book), since post-exposure prophylaxis might be delayed in such places and certain post-exposure products—particularly human rabies immune globulin (HRIG)—may not be readily available. In persons who have already been vaccinated, there is no need for HRIG.
Pre-exposure vaccination is given as a series of three injections—one each on days 0, 7, and 21 or 28. RVA and PCECV should only be given intramuscularly (IM). Pre-exposure HDCV injections may be given either IM or, using a different formulation at a lower dose, intradermally (ID). In contrast, post-exposure vaccine can only be given intramuscularly.
Details about the human vaccines currently licensed in the U.S. are available.
The Pre-exposure Prophylaxis Guide provides the most recent ACIP recommendations pertaining to pre-exposure vaccination.
Currently in Washington, rabies is very rare in the animal species commonly encountered by veterinarians and their staffs, animal control officials, and wildlife workers. Therefore, in this state, such persons do not require routine serologic testing or routine booster vaccination.
