Rabies Exposures Overseas
Special Feature
Synopsis: The risk of rabies during overseas travel or residence is not well defined. In a collaborative study between the Centers for Disease Control and the Catholic Foreign Mission Society of America, this risk was examined for missionaries stationed throughout the world.
Source: Arguin PM, et al. Survey of rabies preexposure and postexposure prophylaxis among missionary personnel stationed outside the United States. J Travel Med 2000;7:10-14.
Arguin and colleagues surveyed current or recently returned missionaries for their knowledge of rabies risk, use of preventive measures, and rabies exposures. They had a response from 44% of those who were mailed surveys, with those in rabies-endemic countries more likely to have returned the surveys. For the 308 persons, in 271 households, stationed in a rabies-endemic country, only 37% knew that there was a rabies risk, and just 23% were counseled to receive vaccine before travel. Once they arrived in their country of service, an additional 13% became aware of a rabies risk, and 23% knew of someone who died of rabies. Twenty-eight percent (87/308) received pre-exposure vaccine. Correlates of receiving vaccine were being assigned to an African country (O.R. = 8.6), younger age (< 40 years) (O.R. = 2.5), and being informed of risk or having vaccine recommended (O.R. = 15.6).
Twenty percent of missionaries reported keeping pets in their homes that were not vaccinated against rabies. There were 38 potential rabies exposures in 22 persons. Dogs accounted for 66% of exposures and humans 20%; 34% of exposures were bites. The highest rate of exposure was in African countries, where one exposure per 1000 persons per month occurred. Postexposure management with wound cleaning, vaccine, and rabies immune globulin (RIG) was complete for only three of the 38 exposures.
Comment by David R. Hill, MD, DTM&H
Although this study was derived from recalled information (some of it from many years prior to the survey, with a low response rate), the message is clear: Many individuals who are living in rabies-endemic countries do not get proper advice about risk and protection before they travel, and most persons receive inadequate postexposure treatment (PET) following a potentially rabid animal exposure.
This observation is reinforced by other data. Hatz and colleagues surveyed Swiss and German expatriates living in tropical countries and documented 72 bite exposures in 58 persons.1 Sixty-nine percent of bites were from dogs. Only 30% of the postexposure management could be considered correct; 51% received nothing and 19% received incomplete treatment. A study from Thailand asked public hospital officials about their management of rabies exposures.2 Thirty-eight percent stated that RIG was not available, 57% said that it was difficult to obtain, and 43% were unaware of the recommendations to infiltrate as much of the volume of RIG as possible into the wound. In Karachi, Pakistan, of 143 postexposure treatments, 69% received inadequate wound care, 100% received nerve cell vaccines, and only 3% received RIG.3 Finally, the death of an American tourist from rabies emphasizes the difficulty of even locating postexposure treatment.4
The solution is also clear, but its implementation is challenging: the risk of rabies should be discussed with all persons traveling to rabies-endemic areas,5 and at-risk persons should be either vaccinated or provided with sufficient information to access PET. Countries that are presumed to be free of rabies can be found in the CDC publication, Health Information for International Travel (also available online at www.cdc.gov).5 The duration of a person’s trip, their activities, and most important, their access to PET needs to be assessed before a decision is made whether to administer pre-exposure vaccine. If a decision is made to vaccinate, it can be safely and effectively done with either of two available rabies vaccines—the human diploid cell vaccine (HDCV, Pasteur Mérieux Connaught) and the purified chick embryo cell vaccine (RabAvert, Chiron). If the intradermal route is used (with HDCV only), care needs to be taken to complete the three-shot series before chloroquine or mefloquine malaria chemoprophylaxis is started.
Otherwise, the intramuscular route may be used. Receiving pre-exposure vaccine does not mean that no further treatment is necessary in the event of exposure. If exposed, the affected area should be washed, and two doses of vaccine should be administered (some countries may have different postexposure schedules). Pre-exposure vaccination provides protection in the event there is delayed access to medical care. It may also provide protection if there is inapparent or unreported exposure (as may occur in children), eliminates the need for RIG, requires fewer doses of postexposure vaccine (usually 2, therefore decreasing the risk of receiving nerve-cell-derived vaccines), and decreases the overall cost of management.
Travelers who do not receive pre-exposure vaccine should be counseled about avoiding potentially rabid animals, particularly dogs, and how to manage a bite exposure. They should thoroughly wash the wound, preferably using a virucidal agent, and then receive rabies vaccine and RIG. They need to know how to access safe and effective PET in the medical care system by being given numbers of American embassies or consulates, or by being provided with information about travel health insurance programs. There may be different schedules for vaccine administration overseas but, if done properly, they should be effective.6 Travelers who return having begun vaccination overseas should have vaccination continued while promptly checking serology to determine if they have responded. Further detailed information about rabies and its prevention can be found in a recent review by Plotkin,7 and the CDC statement on rabies prevention.6 Description of the global epidemiology of rabies and available vaccines can be accessed through RABNET, a WHO-based Internet site: http://oms.b3e.jussieu.fr/rabnetS/. Proper pretravel advice and care and anticipation of potential exposures overseas may be life saving for travelers. (Dr. Hill is Associate Professor of Medicine, Director, International Travelers’ Medical Service, University of Connecticut, Storrs, Conn.)
References
1. Hatz CF, et al. Circumstances and management of 72 animal bites among long-term residents in the tropics. Vaccine 1995;13:811-815.
2. Kositprapa C, et al. Problems with rabies postexposure management: A survey of 499 public hospitals in Thailand. J Travel Med 1998;5:30-32.
3. Parviz S, et al. Postexposure treatment of rabies in Pakistan. Clin Infect Dis 1998;27:751-756.
4. Case records of the Massachusetts General Hospital. Case 21-1998. N Engl J Med 1998;339:105-112.
5. Centers for Disease Control and Prevention. Health Information for International Travel, 1999-2000. 1999, Atlanta, Ga: DHHS.
6. Centers for Disease Control and Prevention. Human rabies prevention—United States, 1999. Recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR Morb Mortal Wkly Rep 1999;48(No. RR-1):1-21.
7. Plotkin SA. Rabies. Clin Infect Dis 2000;30:4-12.
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