June 15, 2012
Dear Mayo Clinic:
I'm planning an overseas mission trip and understand that I need to take medicine to prevent malaria. Is this necessary, and if so, how far in advance do I need to take it? How common is malaria and is it always a serious disease?
If you're planning to travel to tropical locations such as central South America, Haiti, sub-Saharan Africa or south Asia, discuss malaria preventing recommendations with your doctor a couple of months before you leave. He or she can prescribe drugs to take before, during and for some weeks after your trip to help protect you from malaria.
Malaria is a parasitic disease spread by mosquitoes. It can lead to serious illness, and sometimes death. About 1,500 cases are diagnosed in the United States each year. Most occur in travelers who didn't take the right preventive measures.
Malaria is caused by microscopic parasites that are transmitted most commonly by mosquito bites. There are five different species of malarial parasite (Plasmodium) that cause infections in humans. If an infected mosquito bites you and malaria is transmitted, the parasites travel to your liver where they mature and may become dormant. Dormancy can last up to a year, but typically lasts 10 days to four weeks.
When the parasites mature, they leave the liver cells to infect red blood cells. This is when malaria symptoms typically develop. The most common symptoms of malaria are fever, chills and headache.
If an uninfected mosquito bites you at this point, it will become infected and can spread malaria to others. You can also be infected from exposure to infected blood, such as through a blood transfusion.
Malaria is estimated to kill about 1 million people worldwide each year. Most of these deaths occur in Africa, especially among young children.
Malaria infections are categorized as either uncomplicated or severe. Symptoms of uncomplicated malaria are similar to the flu and include moderate to severe chills and shaking, high fever, profuse sweating, headaches, nausea, and vomiting. These bouts of illness may come and go.
If uncomplicated malaria isn't promptly treated, it can become a life-threatening medical emergency. Severe malaria may involve brain swelling and damage, breathing problems as fluid accumulates in the lungs, kidney failure, rupture of the spleen, severe damage to red blood cells, and dangerously low blood sugar.
If you experience a high fever while traveling or living in a part of the world with malaria, you should be evaluated immediately by a local medical facility. In addition, talk to your personal physician promptly if you experience a high fever within a year after returning from a part of the world with malaria. If you have severe symptoms, seek emergency care.
The diagnosis of malaria is made through laboratory analysis of a blood sample by microscopy or molecular analysis. A microscopic exam may also reveal the species of malaria parasite that has infected you. In addition, in some countries or laboratories a rapid blood test can determine in 15 minutes whether or not a malaria infection is present.
Treatment of malaria involves a combination of one or more antimalarial drugs, depending on the type of malaria infection acquired. Treatment is based on severity of infection and the specific species of malaria causing the infection. Treatment may be oral or intravenous. Medications used include chloroquine (Aralen), mefloquine (Lariam), doxycycline, clindamycin, quinine, artemether and lumefantrine (Coartem), primaquine or the combination of atovaquone and proguanil (Malarone).
Effective treatment can cure malaria, but the disease can persist if it's not treated or treated with the wrong drug. Drug choice and treatment intensity are determined by factors such as the specific malaria parasite species, where it was acquired, your age, and the severity of the infection. Drug choice is important, as some types of malaria have evolved to be resistant to certain drugs, such as chloroquine.
Prevention of malaria is based on avoiding insect bites and taking a preventive medication. Medications used for malaria prevention have to be started a few days to a few days to weeks before traveling, and taken daily while you are traveling and for some time after you return. These medications include some of the medications listed above for treatment. In general they are safe and very effective. If you'll be traveling to a location with malaria, be sure to discuss this with your doctor ahead of time.
— Abinash Virk, M.D., Infectious Diseases, Mayo Clinic, Rochester, Minn.