Problems at the Destination

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. It is caused by bacteria or viruses that have contaminated food or water.

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

• Avoiding ice

• 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.

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 medication.

Mosquito bites are prevented by the following measures:

• Wearing long-sleeved shirts and long trousers (especially at dawn and dusk, when mosquitoes are most active)

• Sleeping under a mosquito net

• Using insect repellants that contain diethyltoluamide (DEET) or picaridin

Insect repellants can also help prevent other mosquito-borne diseases such as dengue, Zika, and yellow fever.

Sexually transmitted 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 Prevention of Sexually Transmitted Infections). 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.

Travelers should be advised to check the website of their nation's health agency (CDC in the United States) as well as the destination countries' health agencies for possible health requirements related to COVID-19.

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 and cases are increasing globally. Dengue 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.

In the United States, the dengue vaccine CYD-TDV is approved for use in children and adolescents 9 to 16 years of age who have laboratory-confirmed previous dengue virus infection and are living in an area where dengue is endemic, but is not recommended or available for travelers. The vaccine is also available in Mexico, Brazil, Thailand, and some other countries. Another dengue vaccine (TAK-003) is being evaluated in the United States and is already approved for use in Indonesia, the European Union, and the United Kingdom. This vaccine can be used for individuals who have not had prior dengue infections as well as those who have. Several other dengue vaccines are under investigation.

Mosquito bite prevention is important for people traveling to areas where dengue is common.

• Wear clothing that covers as much of the body as possible

• Use insect repellants, such as DEET (diethyltoluamide) or picaridin

• Avoid exposure to mosquitoes and ticks as much as possible

These measures also offer protection from other insect-transmitted diseases including Zika and chikungunya. (See CDC: Prevent Mosquito Bites.)

Influenza (flu) is a viral infection of the lungs and airways with one of the influenza viruses. It is common in international travelers. An annual influenza vaccines is the best way to prevent influenza.

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.

Lice and scabies

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 CDC recommends that pregnant women consider postponing travel to areas where Zika virus infection is common (see CDC Zika Travel Information).

The following English-language resources may be useful. Please note that THE MANUAL is not responsible for the content of these resources.

1. Centers for Disease Control and Prevention: Travelers' Health

2. Centers for Disease Control and Prevention: Assistance and information to help patients returning from travel abroad

3. International Society of Travel Medicine's Global Clinic Directory: A database of travel clinics around the world