Health issues at the destination are especially important to prevent and avoid in international settings. Certain infections are common when traveling to certain areas, and many people are most concerned about infection when considering a trip overseas. However, motor vehicle crashes and heart disease are the most common causes of death among international travelers. Heart disease is the most common cause of death among nontravelers as well, suggesting that attention to health before leaving home is the best way to prevent illness while away.
Injuries caused by motor vehicle crashes are the most frequent cause of death among younger and middle-aged travelers. Another common cause of death while traveling is drowning. Common-sense measures can be taken to prevent many such injuries. For example, people uncomfortable with unfamiliar traffic patterns (such as driving on the left side of the road in England versus the right side in the United States) can take public transportation or hire drivers familiar with local roads and traffic laws. Travelers should avoid overcrowded taxis, ferries, or other transports and avoid nighttime driving and swimming in poorly lit areas. People should wear seat belts even as passengers and should use a helmet when bicycling. Travelers should avoid motorcycles and mopeds and avoid riding on bus roofs or in open truck beds. Also, alcohol should never be consumed before driving or swimming, even where laws do not formally prohibit such actions or where laws that do exist are not enforced. People should also avoid beaches with turbulent waves, particularly when lifeguards are not present.
Many cities are unsafe after dark, and some are unsafe even during the day. A traveler should avoid walking alone on poorly lit or deserted streets in such cities, especially in countries where the traveler is obviously a stranger.
Fair-skinned travelers are more vulnerable to sunburn at tropical latitudes and at high altitude. Use of high-SPF (sun protection factor of 30 or higher) sunscreen is advisable. When both sunscreen and insect repellent are used, sunscreen should be applied first, then, after at least fifteen minutes, insect repellent.
Traveler’s diarrhea (turista) is the most common health problem among international travelers.
The risk of traveler’s diarrhea may be reduced by the following measures:
Drinking and brushing teeth with bottled, filtered, boiled, UV-treated, or chlorinated water
Eating freshly prepared foods only if they have been heated to steaming temperatures
Eating only fruits and vegetables that people peel or shell themselves
Avoiding food from street vendors
Washing hands frequently
Avoiding all foods likely to have been exposed to flies
Taking certain antibiotics can also prevent traveler’s diarrhea. However, such use has a risk of side effects and may increase the chances that bacteria will develop resistance to antibiotics. Thus, doctors recommend preventive antibiotics only for people who have an immune deficiency disorder.
In most cases, traveler’s diarrhea subsides by itself in about 3 to 5 days and requires only the steady intake of fluids to prevent dehydration. Ordinary clear liquids (without caffeine or alcohol) are adequate for most people. Young children and older people may benefit from powdered rehydration mixes or an oral rehydration solution.
People who have moderate to severe symptoms (symptoms severe enough to disrupt activities) should consider taking an antibiotic, especially if they have vomiting, fever, abdominal cramps, or blood in the stool. Azithromycin is appropriate for most countries and is recommended for children and pregnant women. People should contact their doctor for an antibiotic prescription before travel. If people are 6 years of age or older and have no bloody stools, fever, or abdominal pain, they can also be treated with the antidiarrheal drug loperamide (which is available without a prescription).
For older adults and young children, powdered rehydration mixes are available for travel. If these mixes are unavailable, rehydration solutions can be made by adding 6 teaspoons of sugar and 1 half teaspoon of salt to 1 liter of water. However, solutions should be prepared carefully because young children can become seriously ill or die if they drink much of a solution that has been incorrectly mixed (for example, if a rehydration mix has not been fully diluted).
Malaria is common throughout the tropics. Malaria is prevented by avoiding mosquito bites and taking an antimalarial drug.
Mosquito bites are prevented by the following measures:
Even when people take measures to avoid mosquito bites, it is still necessary to take a drug to prevent malaria (such as mefloquine, chloroquine, doxycycline, or atovaquone/proguanil) when traveling to many parts of the world. Information about specific areas is available from the Centers for Disease Control and Prevention (CDC: Malaria and Travelers).
Pregnant women should consider delaying travel to areas where malaria is common because malaria is more likely to be serious and life threatening among pregnant women than among women who are not pregnant, even when preventive drugs are used. Pregnant women who cannot postpone travel must weigh the risks of taking protective drugs, the effects of which on pregnancy are not well known, against the risks of traveling without protection.
Sexually transmitted diseases (infections), including human immunodeficiency virus (HIV) infection, gonorrhea, syphilis, trichomoniasis, and hepatitis B, are more common in low- and middle-income countries. All can be prevented through abstinence or with correct, consistent use of a latex condom (see Overview of Sexually Transmitted Diseases (STDs) : Prevention). Because HIV and hepatitis B also are transmitted through blood and needles, an international traveler should not accept a blood transfusion without assurance that the blood has been tested for infection. Also, injections should be accepted only through one-time-only disposable needles.
COVID-19 is an acute respiratory illness that can be severe and is caused by a newly identified coronavirus officially named SARS-CoV2. The COVID-19 pandemic necessitated limitation of travel to and from various countries. Travelers should check the website of their nation's health agency (for example, in the United States, the Centers for Disease Control and Prevention) for current recommendations.
Dengue is a mosquito-borne viral infection that causes fever, generalized body aches, and, if severe, external and internal bleeding (called dengue hemorrhagic fever). Dengue is common in the tropics and subtropics worldwide. It is most common in Southeast Asia but has become more common in Central and South America and other countries. It has occurred in the Caribbean (including Puerto Rico and the U.S. Virgin Islands), in Oceania, and in the Indian subcontinent.
A vaccine is available in Mexico, Brazil, Thailand, and some other countries (not in the United States), but use is restricted to people who have previously had dengue.
Mosquito bite prevention is important for people traveling to areas where dengue is common.
Schistosomiasis is a common and potentially serious infection caused by a parasite that lives in freshwater in Africa, Southeast Asia, China, and eastern South America. The risk of schistosomiasis can be reduced by avoiding freshwater activities in areas where schistosomiasis is common. Asymptomatic travelers with freshwater exposure in regions where schistosomiasis is common should be screened for the parasite after returning from such regions.
Zika virus infection causes few or only mild symptoms in adults. However, Zika infection during pregnancy can cause serious birth defects in the baby.
Zika virus infection is spread by mosquitoes and also by sexual contact and transfusion of blood from an infected person. The disease has spread widely through South and Central America, the Caribbean, South Asia, Southeast Asia, and Pacific Islands. The Centers for Disease Control and Prevention (CDC) recently reported that all of the cases of Zika virus infection in the United States were in travelers returning from affected areas. There were no reports of Zika virus infection spread by local mosquitoes or through sexual contact. The CDC recommends that pregnant women consider postponing travel to areas where Zika virus infection is common (see CDC: Zika Virus: For Pregnant Women and CDC Zika Travel Information).