Natural Disasters and Environmental Hazards

Natural Disasters

Travellers 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. However, floods have been known to prompt outbreaks of leptospirosis in areas where the organism is found in water sources. (See Chapter 4, "Prevention of Specific Infectious Diseases: Leptospirosis," for information on how to minimize the risk of infection.)

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 "Risks From Food and Water".) Travellers 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 for wounds that have been exposed to water that may contain parasites or bacteria. Tetanus booster status should always be kept current.

Travellers 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. Travellers should exercise caution during clean-up, particularly when encountering downed power lines, water-affected electrical outlets, interrupted gas lines, and stray or frightened animals. 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). When arriving at a destination, travellers should be familiar with local risks for seismic, flood-related, landslide-related, and other hazards, as well as 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 arthrospores leading to coccidioidomycosis). Health risks associated with these environmental occurrences have not been fully studied. Travellers with chronic pulmonary disease may be more susceptible to adverse effects from these exposures. Breathing and swallowing dust when travelling on unpaved roads or in arid areas can be followed by nausea and malaise. 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 travellers to such areas is probably small; however, avoidance of dust clouds and areas of heavy dust or haze may be wise. In some very dusty settings, travellers may find it useful to cover the nose and mouth with a handkerchief or disposable surgical mask to reduce the inhalation of larger particles.

Environmental Hazards

Water

Rivers and lakes may be contaminated with organic or inorganic chemical compounds (e.g., heavy metals or other toxins) that can be harmful 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

Travellers 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. In April 1986, this region, in Ukraine about 100 kilometers (62 miles) northwest of Kiev, Ukraine, and 310 km (193 miles) southeast of Minsk, Belarus, had the largest short-term release of radioactive materials into the atmosphere ever recorded. This radiologic contamination primarily affected three republics: Ukraine, Belarus, and Russia. The highest radioactive ground contamination occurred within 30km (19 miles) of Chernobyl. The level of contamination in any given area is decreasing with time, but it will be many years before levels of radioactivity in some parts of these countries return to those before the event.

Short-term international travellers (those who plan to stay in such regions less than a few months) should not be concerned about residing in areas that are not controlled (marked with signs or fenced). However, long-term travellers are advised that, in some uncontrolled areas, they could receive a radiation dose from the radioactive ground contamination in excess of the international radiologic health standards recommended for the public. Travellers should investigate local conditions before choosing a long-term residence. (For example, ground contamination that exceeds 5 curies per square kilometer [>5 Ci/km2] of cesium-137 could result in a radiation dose greater than the recommended standards.) Staff of the U.S. embassy should be able to assist in this investigation.

Officials in affected areas attempt to monitor all foodstuffs sold in the public markets for levels of radioactivity. Radioactive concentration limits have been established for various classes of food (e.g., milk, meat, and vegetables). These limits are comparable with standards used by many western nations, including the European Union. Foods with contamination levels in excess of these limits are not allowed to be sold in the markets. Private farmers in affected regions regularly make foods available for sale outside the official market system. These foods are not monitored for radioactivity, and travellers should not eat them. Likewise, travellers are advised not to eat any wild berries, wild mushrooms, or wild game from these regions and to drink only bottled water.

Young children, unborn babies, and nursing infants are potentially at greater risk from exposure to radiation than adults. Pregnant or nursing mothers are advised to acquire food from reliable, well-monitored sources when visiting affected regions.

Travellers should also exercise caution when they encounter objects or equipment that seem to be discarded, misplaced, or abandoned. Lost radioactive sources are still a persisting issue, particularly in countries lacking effective radiation control programs. Such misplaced objects may or may not bear the radioactive symbol. If a questionable object is encountered, appropriate authorities should be notified.

Bibliography
  • Eisenbud M, Gessel, T. Environmental radioactivity from natural, industrial, and military sources. 4th ed. San Diego, CA: Academic Press; 1997.
  • Noji EK, editor. The public health consequences of disasters. New York: Oxford University Press; 1996.
  • Pan American Health Organization. Natural disasters: protecting the public's health [monograph on the Internet]. Washington, DC: PAHO; 2000 [cited 2004 Oct 21]. Available from: http://www.paho.org/English/Ped/SP575/SP575_prelim.pdf.
  • U.S. Food and Drug Administration. Accidental radioactive contamination of human food and animal feeds: recommendations for state and local agencies [monograph on the Internet]. Rockville, MD: U.S. Food and Drug Administration; 1998 [cited 2004 Oct 21]. Available from: http://www.fda.gov/cdrh/dmqrp/84.html.
  • 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.

- Josephine Malilay, Dahna Batts-Osborne, Charles W. Miller, and Armin Ansari

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