Malaria and International Travel

What's the Problem?

Although malaria is very rarely transmitted in the United States, it is the number one life-threatening infectious disease of international travelers, including travelers from the U.S. who go to malaria-risk areas. Malaria is caused by a parasite transmitted by the bite of an infected female Anopheles mosquito. Malaria symptoms include fever and flu-like symptoms, such as shaking chills, muscle aches, headache, fatigue, cough, and sometimes nausea, vomiting, and diarrhea. Untreated malaria can lead to seizures, kidney failure, coma, and death. Some species of malaria may remain dormant in the liver and cause a reappearance of symptoms months or even years after the initial onset of symptoms. Worldwide, malaria causes more than one million deaths each year; some 300 million new cases are reported annually. About 1,000 cases are diagnosed and reported in the United States each year. However, estimates are that some 30,000 Europeans and North Americans become infected while traveling abroad.

Who's at Risk?

Anyone who lives or travels in an area with malaria transmission is at risk. Malaria occurs in many tropical and sub-tropical countries throughout Central and South America, Hispaniola, Asia, Southeast Asia, the Indian subcontinent, sub-Saharan Africa, the Middle East, and Oceania. People who grow up in or have spent years in areas where malaria is prevalent develop a protective immunity after repeated attacks, but this immunity is quickly lost after leaving the risk area. Immunity to malaria is not life-long.

Can It Be Prevented?

Yes. Malaria is prevented by taking antimalarial drugs and by preventing mosquito bites. Travelers should see a health care provider before travel for a prescription for their antimalarial drug. The drug should be started prior to travel. The traveler should continue to take their drugs while in the malaria-risk area and after returning home. Unfortunately, most health insurance plans do not provide reimbursement for these drugs, but the benefits outweigh the cost to the traveler. However, no malaria drug is 100% effective, thus a person who experiences symptoms should seek prompt medical attention. Early diagnosis and treatment can prevent serious illness and death.

Preventing mosquito bites is also important. Insect repellents containing DEET should be worn when out of doors. Use a DEET concentration up to 35%. Time-release products provide a longer length of protection. In addition, wear covering clothing such as long-sleeved shirts, long pants, and thick socks. Sleep under a mosquito net if not staying in screened or air-conditioned housing.

The Bottom Line

• CDC travel health recommendations and information are free on the CDC Travelers' Health website.
• Travelers (including children) need to see a health care provider 4 to 6 weeks before traveling to a malaria risk area. For a list of travel medicine clinics see The International Society of Travel Medicine (ISTM).
• Preventing mosquito bites will reduce the risk for contracting malaria and other insect-borne diseases.
• Antimalarial drugs need to be taken as prescribed, before and after travel.
• Malaria may still be contracted when people take all precautions. If symptoms occur, people need to seek medical attention as soon as possible.

Case Example

Indira just graduated from high school and is taking her first trip to India, her parents' birthplace, as a graduation present. She does not seek medical attention because her parents and others have traveled many times to India without incident. In her parents' hometown she stays with relatives in modern housing that only lacks air-conditioning and window screens. She sleeps under bed netting and is occasionally bothered by mosquitoes. Indira returns to the U.S. and college. A month later, she develops a fever and chills; she sees the doctor in the school clinic but is sent home with a presumed case of the flu. The clinic physician did not ask Indira if she had recently traveled to a malaria-risk area. While at home, Indira's symptoms worsen. She is admitted to the hospital following a seizure and undergoes extensive testing. A blood smear is finally done; cerebral malaria is diagnosed.