Natural Disasters

Travelers should be aware of the potential for natural phenomena such as hurricanes, tornados, or earthquakes. Natural disasters can contribute to the transmission of some diseases, especially since water supplies and sewage systems may be disrupted. However, transmission cannot take place unless the causative agent is in the environment. Although typhoid can be endemic in developing countries, natural disasters have seldom led to epidemic levels of disease (1). However, floods have been known to prompt outbreaks of leptospirosis in areas where the organism is found in water sources (see Chapter 4.).

When water and sewage systems have been disrupted, safe water and food supplies are of great importance in preventing enteric disease transmission. If contamination is suspected, water should be boiled and appropriately disinfected (see Chapter 2). Travelers who are injured during a natural disaster should have a medical evaluation to determine what additional care may be required for wounds potentially contaminated with feces, soil, or saliva or that have been exposed to fresh or sea water that may contain parasites or bacteria. Tetanus booster status should always be kept current (1).

Travelers also should be aware of the risks for injury before, during, and after a natural disaster. In floods, people should avoid driving through swiftly moving water. Travelers should exercise caution during clean-up, particularly when encountering downed power lines, water-affected electrical outlets, interrupted gas lines, and stray or frightened animals (2). During natural disasters, technological malfunctions may release hazardous materials (e.g., release of toxic chemicals from a point source displaced by strong winds, seismic motion, or rapidly moving water) (3). When arriving at a destination, travelers should be familiar with local risks for seismic, flood-related, landslide-related, tsunami-related, and other hazards, as well as warning systems, evacuation routes, and shelters in areas of high risk.

Natural disasters often lead to wide-ranging air pollution in large cities. Uncontrolled forest fires have caused widespread pollution over vast expanses of the world. Natural or manmade disasters resulting in massive structural collapse or dust clouds can cause the release of chemical or biologic contaminants (e.g., asbestos or the arthrospores that lead to coccidioidomycosis) (4,5). Health risks associated with these environmental occurrences have not been fully studied. Travelers with chronic pulmonary disease may be more susceptible to adverse effects from these exposures.

Typically, following natural disasters of magnitude that may impact travelers, current information about the disaster as well as travel health information specific to those needing entry into such regions is provided on the CDC Travelers’ Health website (wwwn.cdc.gov/travel). Recommendations may include specific immunizations or cautions regarding unique hazards in the affected area.

Environmental Hazards

Air

Air pollution may be found in large cities throughout the world; its sources are often attributed to automobile exhaust and industrial emissions and may be aggravated by climate and geography. The harmful effects of air pollution are difficult to avoid when visiting some cities; limiting strenuous activity and not smoking can help. Any risk to healthy short-term travelers to such areas is probably small, but persons with preexisting health conditions (e.g., asthma or chronic obstructive pulmonary disease) could be more susceptible. Avoidance of dust clouds and areas of heavy dust or haze may be wise.

Water

Rivers and lakes may be contaminated with organic or inorganic chemical compounds (e.g., heavy metals or other toxins) and harmful algal blooms (e.g., cyanobacteria) that can be toxic both to fish and to people who eat the fish or who swim or bathe in the water. Rivers, lakes, and the ocean contaminated with pathogens from human and animal waste may also cause disease in swimmers. Such hazards may not be immediately apparent in a body of water.

Radiation

Natural background radiation levels can vary substantially from region to region, but these natural variations are not a health concern for either the traveler or resident population (6,7) Travelers should be aware of regions that are known to have been contaminated with radioactive materials, such as the area surrounding the Chernobyl nuclear power station, 100 kilometers (62 miles) northwest of Kiev, Ukraine. This unprecedented radiation emergency and subsequent contamination primarily affected regions in three republics: Ukraine, Belarus, and Russia, with the highest radioactive ground contamination within 30 km (19 miles) of Chernobyl (8).

In most countries, known areas of radioactive contamination are fenced or marked with signs. These areas should not be trespassed. Any traveler seeking long-term (more than a few months) residence near a known or suspected contaminated area should consult with staff of the nearest U.S. embassy and inquire about any applicable advisories in that area regarding drinking water quality or purchase of meat, fruit and vegetables from local farmers (9).

Radiation emergencies are rare events. In case of such an emergency, however, travelers should follow instructions provided by local emergency and public health authorities. If such information is not forthcoming, travelers should immediately seek advice from the nearest US embassy. Natural disasters (such as floods) may also result in displacement of industrial or clinical radioactive sources. In all circumstances, travelers should exercise caution when they encounter unknown objects or equipment, especially if they bear the radioactive symbol. If a questionable object is encountered, appropriate authorities should be notified.

References

1. Pan American Health Organization. Natural disasters: protecting the public’s health [monograph on the Internet]. Washington, DC: PAHO; 2000 [cited 2006 Jun 21]. Available from: http://www.paho.org/English/dd/ped/SP575.htm.
2. Noji EK, ed. The public health consequences of disasters. New York: Oxford University Press; 1996.
3. Young S, Balluz L, Malilay J. Natural and technologic hazardous material releases during and after natural disasters: a review. Sci Total Environ. 2004;322:3-20.
4. Nukushina J. Japanese earthquake victims are being exposed to high density of asbestos: we need protective masks desperately. Epidemiol Prev. 1995;19:226-7.
5. S.chneider E, Hajjeh RA, Spiegel RA, Jibson RW, Harp EL, Marshall GA, et al. A coccidioidomycosis outbreak following the Northridge, Calif, earthquake. JAMA. 1997 Mar 19;277:904-8.
6. National Council on Radiation Protection and Measurements, NCRP Report No. 94, Exposure of the Population in the United States and Canada from Natural Background Radiation, Bethesda, Md: 1987.
7. Eisenbud M, Gessel T. Environmental radioactivity from natural, industrial, and military sources. 4th ed. San Diego, CA: Academic Press; 1997.
8. United Nations Scientific Committee on the Effects of Atomic Radiation. UNSCEAR 2000 Report to the General Assembly, Sources and Effects of Ionizing Radiation, Annex J, Exposures and Effects of the Chernobyl Accident. New York: United Nations, 2000.
9. U.S. Food and Drug Administration. Accidental Radioactive Contamination of Human Food and Animal Feeds: Recommendations for State and Local Agencies. Rockville, MD: U.S. Food and Drug Administration; 1998 [cited 2006 Jun 22].

JOSEPHINE MALILAY, DAHNA BATTS-OSBORNE, CHARLES W. MILLER, ARMIN ANSARI