Rabid Bat Rabies Warning (cont.)

Reported by: A Deckert, MD, Shasta County Public Health, Redding; C Glaser, MD, Viral and Rickettsial Disease Laboratory; B Sun, DVM, Div of Communicable Disease Control, California Dept of Health Svcs. Div of Viral and Rickettsial Diseases, National Center for Infectious Diseases; L Demma, PhD, EIS Officer, CDC.

Editorial Note:

Although human rabies is rare in the United States, clinicians and public health workers should suspect rabies when a history of possible bat contact is known or when unexplained atypical progressive neuropathy or unusual febrile encephalitis is observed. Persons coming in direct contact with bats should seek consultation with their health-care providers immediately to receive PEP, if appropriate.

Rabies is an acute, progressive, and fatal disease. The only documented survivors received rabies prophylaxis before the onset of illness. However, an aggressive approach to therapy might be attempted in patients who are in an early stage of clinical disease (1). A combination of therapies is suggested, including rabies vaccine, rabies immune globulin, ribavirin, interferon-alpha, mono clonal antibodies, and ketamine. The patient described in this report visited the ED at an early stage with a predominant symptom of paraesthesia at the bite site. He was treated within approximately 24 hours of admission, albeit unsuccessfully, with the first four of these agents.

This fatality follows two other recent bat-associated cases of human rabies in California (in Glenn County in 2002 and in Amador County in 2000) (2,3). However, these cases were associated with a Mexican free-tailed bat (Tadarida brasiliensis) rabies virus variant, and neither patient identified a definitive bat exposure. During 1990--1998, of 22 bat-associated rabies infections, 16 (75%) were associated with the virus variant found among silver-haired and eastern pipistrelle bats (4). Properties of these viruses might allow infection and replication under broader conditions than those of other rabies virus variants (5).

During 1990--2000, a total of 24 (75%) of 32 U.S. human rabies cases were caused by bat-associated rabies virus variants. In 22 (92%) of these cases, no documentation of a bite existed; however, this does not mean that a typical bite exposure did not take place. Instead, such a history was not uncovered during presentation or case investigation.

Human rabies is preventable with the proper and timely administration of rabies PEP (6). However, if a patient does not recognize the risk associated with an animal bite, PEP probably will not be obtained. When a bat is found in living quarters and a strong possibility exists that an exposure might have occurred, the animal should be submitted to a local public health laboratory for diagnostic testing. However, if the animal is not available for testing, PEP should be administered when there is a strong probability of exposure.

No laboratory-confirmed cases of human-to-human transmission from patients to health-care workers or family members have been documented. Delivery of health care to a patient with rabies is not an indication for PEP unless a bite has occurred or an exposure of mucous membranes or nonintact skin to potentially infectious body fluids has occurred (6). Adherence to standard safety precautions for health-care workers will minimize the risk for exposure.

Public health professionals need to reemphasize effective measures to reduce animal exposure and to keep pet and livestock vaccinations current. Persons who are bitten by a potentially rabid animal should immediately 1) disinfect and wash the wound, 2) capture the animal safely, 3) contact the local health department, and 4) see a physician for evaluation about the need for PEP.

Acknowledgments

This report is based on data contributed by E Osvold-Doppelhauer, Trinity County Health Dept, Weaverville; C Lakmann, K Thomas, Shasta County Public Health; H Birk, MD, KK Shwe, MD, S Menezes, MD, M O'Brien, MD, L Dayton, MD, Mercy Medical Center, Redding; D Schnurr, PhD, S Honarmand, C Kohlmeier, Viral and Rickettsial Disease Laboratory, Div of Communicable Disease Control, California Dept of Health Svcs. L Orciari, MS, M Niezgoda, MS, Div of Viral and Rickettsial Diseases, National Center for Infectious Diseases, CDC.

Source: Centers for Disease Control MMWR Weekly, January 23, 2004


Last Editorial Review: 1/26/2004