As the temperature rises, so do reports of animal bites and bat exposures. Typically, about half of all animal bites reported to Public Health – Seattle & King County each year are reported between June and September.

Washington State law requires health care providers to report animal bites received by humans immediately. King County providers are also requested to report bat exposures, and cases where rabies post exposure prophylaxis (PEP) is prescribed. Bat exposures include bare-skin contact with a bat, and situations where bat-to-skin contact or bat bites cannot be ruled out, for example, when a bat is found in a room with a child or inebriated person, or if an adult wakes up to find a bat in the room. These exposures are reportable so that Public Health can: 1) assist health care providers in assessing the risk for rabies, 2) help determine the need for rabies post-exposure prophylaxis, and 3) facilitate laboratory testing of animals for rabies, if indicated.

From 2003 to 2005, 181 persons reported to Public Health in King County met the criteria to receive rabies PEP. Sixteen of these persons were exposed to bats who subsequently tested positive for rabies (10 total bats tested positive and 16 people had been exposed). In 165 cases, no animal was available for testing or observation. Approximately 10 percent of people who are recommended to receive rabies PEP each year in King County were bitten by an animal while traveling outside the US . Follow-up for these cases can be complex because rabies PEP initiated outside the United States may include the administration of biologics that are not approved by the US Food and Drug Administration (such as vaccines of nerve tissue origin), the schedule or dosage for vaccine or rabies immune globulin (RIG) may differ from the US schedule, and RIG is not always available. In these situations, Public Health provides recommendations for post exposure vaccine and/or RIG on a case-by-case basis, at times in consultation with the Centers for Disease Control and Prevention (CDC).  

Although rare, rabies cases still occur in humans in the US . One or two deaths each year are attributed to human rabies, and there may be additional unrecognized deaths due to rabies in the US . In 2004, 3 transplant recipients died from rabies after receiving solid organ transplants from a donor who died with undiagnosed rabies. The most recent rabies death in the US occurred in a Texas teenager in May 2006. Four to six weeks prior to his death, the teenager awoke due to direct contact with a bat in his bedroom. The bat was disposed of and therefore was not available for rabies testing, and public health officials were not consulted. The teenager did not seek medical care until symptoms of rabies developed, at which point it was too late to administer PEP.

Between 1990 and 2000, 24 of the 32 reported human rabies cases in the US were caused by rabies virus strains associated with bats, and in the majority of these cases, a bite from a bat was not documented. In Washington State , the most recent human cases, (in 1995 in Lewis County and in 1997 in Mason County ), were both due to infection with bat rabies strains. The primary reservoir for rabies in Washington State is bats and, though no rabies cases have been identified in wild terrestrial animals in Washington in the past 60 years, there is currently no active surveillance for rabies among these animals. Approximately 8 percent of bats tested in Washington State between 1960 and 2004 were positive for rabies.

Rabies is preventable with timely and appropriate care. Health care providers should advise persons who have been bitten by an animal to wash the wound with soap and water and consult with Public Health about how to manage the animal. In addition, health care providers should immediately call Public Health – Seattle & King County (206-296-4774), preferably before beginning PEP.  Public Health staff include physicians and veterinarians, and are available 7 days a week, 24 hours a day for consultation. Public Health staff can recommend whether testing or confinement and observation of the animal is appropriate.  In the case of bat exposures, it is especially important to capture and test the bat in order to avoid unnecessary administration of PEP, because most bats do not have rabies. Information about how to capture bats without exposing additional persons is available at: www.metrokc.gov/health/prevcont/bats.htm.

Cats, dogs, and ferrets who aren't exhibiting signs of rabies at the time of the bite can be observed for a 10 day quarantine period. If the animal survives this 10 day observation period in good health it means the animal would not have been infectious for rabies at the time of the bite and the person who was bitten does not need rabies PEP. If the animal becomes sick or dies during this period, testing for rabies should be done. 

For people who have never been immunized for rabies, PEP after a potential rabies exposure consists of 5 doses of rabies vaccine given intramuscularly on days 0, 3, 7, 14, and 28, and RIG (dosage based on body weight), administered at the site of the wound (if possible). RIG is given at the same time as the first dose of vaccine. In King County, RIG is typically available only through hospital emergency departments and hospital-based urgent care clinics, however, rabies vaccine for doses 3, 7, 14 and 28, can be ordered by any health care provider through most vaccine distributors in King County, and overnight delivery is often available.

Additional information on rabies and decision trees for assessing the need for PEP is also available at:

• Public Health - Seattle & King County, Rabies Q & A
  
  
• Human Rabies Prevention - United States, 1999 Recommendations of the Advisory Committee on Immunization Practices (ACIP)