Chapter 2The Pre-Travel ConsultationCounseling & Advice for Travelers
Natural Disasters & Environmental Hazards
Travelers should be aware of the potential for natural phenomena such as hurricanes, floods, tsunamis, tornadoes, or earthquakes. Natural disasters can contribute to the transmission of some diseases, especially since water supplies and sewage systems may be disrupted; sanitation and hygiene may be compromised by population displacement and overcrowding; and normal public health services may be interrupted.
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.
The risk for infectious diseases among travelers to affected areas is minimal unless a disease is endemic in an area before the disaster, because transmission cannot take place unless the causative agent is present. Although typhoid can be endemic in developing countries, natural disasters have seldom led to epidemic levels of disease. Floods have been known to prompt outbreaks of leptospirosis and cholera in areas where the organism is found in water sources (see the Leptospirosis and Cholera sections in Chapter 3).
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 or disinfected (see the Water Disinfection for Travelers section earlier in this chapter). 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.
Various vaccine-preventable diseases have been eliminated or are near elimination in some developing countries. However, if someone who has the disease travels to the country, the disease could be reintroduced, leading to an outbreak. Therefore, it is very important that people traveling to offer relief or other services in countries affected by natural disasters be protected against such diseases or not be sick when entering a country.
After a natural disaster, deaths are rarely due to infectious diseases. Rather they are most often due to blunt trauma, crush-related injuries, or drowning. Therefore, travelers should be aware of the risks for injury 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. During natural disasters, technological malfunctions may release hazardous materials (such as release of toxic chemicals from a point source displaced by strong winds, seismic motion, or rapidly moving water).
Natural disasters often lead to wide-ranging air pollution in large cities. For example, uncontrolled forest fires have caused widespread pollution over vast expanses. Natural or manmade disasters resulting in massive structural collapse or dust clouds can cause the release of chemical or biologic contaminants (such as asbestos or the arthrospores that lead to coccidioidomycosis). Health risks associated with these environmental occurrences have not been fully studied. Travelers with chronic pulmonary disease or who are immunocompromised may be more susceptible to adverse effects from these types of exposures.
Typically, after natural disasters of a magnitude that may affect travelers, current information about the disaster, as well as travel health information specific to those needing to travel to the affected area, is provided on the CDC website (www.cdc.gov/travel). Recommendations may include specific immunizations or cautions about unique hazards in the affected area.
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. Specifically, particulate matter (PM), or particle pollution, consisting of fine particles 2.5 µm or smaller in diameter, may enter the lungs and cause serious health problems. Travelers should be aware that global long-term average PM2.5 concentrations have been estimated to exceed the World Health Organization’s Air Quality PM2.5 Interim Target-1 (35 µg/m3 annual average) in eastern and central Asia and North Africa.
Although 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 people with preexisting health conditions (such as asthma, chronic obstructive pulmonary disease, or heart disease) could be more susceptible. Avoiding dust clouds and areas of heavy dust or haze is wise.
Rivers, lakes, and oceans may be contaminated with organic or inorganic chemical compounds (such as heavy metals or other toxins); harmful algal blooms (cyanobacteria) that can be toxic both to fish and to people who eat the fish, or who swim or bathe in the water; and pathogens from human and animal waste that may cause disease in swimmers. Such hazards may not be immediately apparent in a body of water. Available drinking water may also be contaminated; see the Water Disinfection for Travelers section earlier in this chapter for guidance on ensuring water is safe to drink.
Extensive water damage after major hurricanes and floods increases the likelihood of mold contamination in buildings. Travelers may visit flooded areas overseas as part of emergency, medical, or humanitarian missions. Mold is a more serious hazard for people with conditions such as impaired host defenses or mold allergies. To prevent exposure that could result in adverse health effects from disturbed mold, people should adhere to the following recommendations:
- Avoid areas where mold contamination is obvious.
- Use personal protective equipment (PPE), such as gloves, goggles, and a tight-fitting approved N-95 respirator. Travelers should take sufficient PPE with them, as these may be scarce in the countries visited.
- Keep hands, skin, and clothing clean and free from mold-contaminated dust.
- Review the CDC guidance, Mold Prevention Strategies and Possible Health Effects in the Aftermath of Hurricanes and Major Floods (www.cdc.gov/mmwr/preview/mmwrhtml/rr5508a1.htm), which provides recommendations for dealing with mold in these settings.
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. Travelers should be aware of regions known to have been contaminated with radioactive materials, such as the areas surrounding the Chernobyl nuclear power plant in Ukraine and the Fukushima Daiichi nuclear power plant in Japan.
The Chernobyl plant is located 100 km (62 miles) northwest of Kiev. This 1986 accident contaminated regions in 3 republics—Ukraine, Belarus, and Russia—with the highest radioactive ground contamination within 30 km (19 miles) of Chernobyl.
The Fukushima Daiichi plant is located 240 km (150 miles) north of Tokyo. The area within a 20-km (32-mile) radius of the plant is restricted, and Japanese authorities also advised evacuation from locations farther away to the northwest of the plant. This incident occurred in 2011, and as Japanese authorities continue to clean the affected areas and monitor the situation, travel advisories may change. US travelers are advised to check the website of the US embassy in Tokyo for up-to-date information. There are no travel advisories for Tokyo or any city or region south of Tokyo. Travelers who choose to reside for >1 year within 80 km of the Fukushima Daiichi nuclear plant should consult with local authorities to receive guidance on expected levels of radiation and recommendations for reducing exposure to radiation. In addition, pregnant women, children, and the elderly should avoid residing within 30 km of the Fukushima Daiichi Nuclear Plant.
More than 450,000 travelers to the United States originate from Japan each month. During the height of the Fukushima releases, there was some concern about those travelers bringing contamination into the United States with them. Based on radiologic contamination screening at points of entry into the United States, 3 travelers arriving from Japan after the incident had low levels of contamination and were not considered to pose a health hazard to themselves or others.
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 US embassy and inquire about any applicable advisories in that area regarding drinking water quality or purchase of meat, fruit, and vegetables from local farmers. 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, US travelers should immediately seek advice from the nearest US embassy.
Natural disasters (such as floods) may also displace 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. Travelers who encounter a questionable object should notify authorities.