MALARIA PREVENTION  map 

the short version

Where there is malaria, you may become seriously ill if you don't take your pills as prescribed (either every day or every week). Please see the related handout on Mosquito Precautions. You may find the rest of this information interesting.

the long version

Malaria is caused by one-celled animals (called Plasmodia) transmitted by the bite of an infected female anopheles mosquito. Malaria causes fever, chills, headache, muscle aches and a general ill feeling; symptoms usually occur at intervals. Malaria may cause kidney failure, coma or death. Deaths due to malaria are preventable by using preventive medicines. Information on malaria risk in specific countries is available from various sources. The World Health Organization and the Centers for Disease Control are the best sources, but factors such as local weather conditions, mosquito density and prevalence of infection may have a different effect on local malaria transmission patterns from year to year. Locals will often provide useful information, but travelers need to be aware that locals sometimes minimize risk of a variety of diseases.

YOUR RISK OF CATCHING MALARIA Malaria transmission occurs in large areas of Central and South America, Hispanola, sub-Saharan Africa, the Indian subcontinent, Southeast Asia, the Middle East and Oceania, and is restricted to rural areas in some countries. The estimated risk of acquiring malaria may vary widely depending on intensity of transmission, itinerary, time of year, time of day and type of travel. American travelers import about 1000 cases into the US annually. About 60% of imported malaria (and most fatal cases; overall, about 4% of malaria is fatal) were acquired in sub-Saharan Africa, even though only an estimated 500,000 Americans travel there each year. In contrast, an estimated 21 million Americans travel to malarious areas of Asia and Latin America each year (including 19 million to Mexico) and bring home far fewer (about 30%) of the cases. This disparity in the risk of acquiring malaria is probably because travelers to Africa tend to spend considerable time (especially evening and nighttime hours) in rural areas where malaria risk is highest.

Estimating the risk of infection for different travelers is difficult, even among those who travel or reside temporarily in the same general areas within a country. For example, tourists staying in air-conditioned hotels are at lower risk than backpackers or adventure travelers. Similarly, long-term residents living in screened and air-conditioned housing are less likely to be exposed than missionaries or Peace Corps volunteers.

GENERAL ADVICE FOR TRAVELERS TO MALARIA ENDEMIC AREAS All travelers to malarious areas of the world are advised to use medications and personal protection measures to prevent malaria; however, travelers should be aware that regardless of methods employed, malaria still may be contracted. Malaria symptoms may develop as early as 8 days after initial exposure and as late as several months after departure from malarious area, and can occur after preventive medicines have been stopped, months after return. Travelers should understand that malaria can be treated effectively and easily early in the course of the disease, but that delay of appropriate therapy can have serious or even fatal consequences. Individuals who have symptoms of malaria should seek prompt medical evaluation including thick and thin blood smears as soon as possible.


CHEMOPROPHYLAXIS (prevention with medicines) When used as directed, these medications provide 99% protection from malaria. Malaria preventive treatment should usually begin before travel to malarious areas, should continue during travel in the malarious areas, and after leaving the malarious areas.

Malaria Prevention Regimens
**regimen A: For travel to areas of risk where chloroquine resistance has NOT been reported, once weekly use of chloroquine alone is recommended. The weekly dose is 500 mg, either one (1) 500 mg pill or two (2) 250 mg pills weekly. Chloroquine is usually very well tolerated. The few people who experience uncomfortable side effects may tolerate the drug better by taking it with meals or in twice-weekly doses. As an alternative, the related compound hydroxychloroquine may be better tolerated. Chloroquine should begin 1 week before travel to malarious areas. It should be continued weekly during travel and for 4 weeks after leaving the area.

**regimen B: For travel to areas where chloroquine resistance DOES exist, use of mefloquine alone is the drug of first choice. Mefloquine (Lariam) should begin 1 week before travel to malarious areas. It should be continued weekly during travel and for 4 weeks after leaving the malarious area. Test doses of Lariam may be recommended (please see the chart below). NOTE: In some countries a fixed combination of mefloquine and Fansidar is marketed under the name Fansimef. Fansimef should not be confused with mefloquine and is not recommended for prevention of malaria.
 

ADVERSE EFFECTS OF ANTIMALARIALS
Chloroquine and hydroxychloroquine may infrequently cause nausea, headache, dizziness, blurred vision or itching when taken in preventive doses for malaria, but generally these do not require stopping the drug. High doses of chloroquine used to treat rheumatoid arthritis have been associated with eye disease, but not with the very low doses used for malaria prevention or treatment. Chloroquine has been reported to worsen psoriasis. Chloroquine is so safe that it may be used to treat pregnant women.

Mefloquine (Lariam) can cause nausea and dizziness in preventive doses, but these symptoms tend to be mild, brief and self-limited. Vivid dreams and restless sleep may occur, and do not necessitate stopping treatment. Serious adverse reactions (confusion, psychosis, hallucinations or convulsions) are rare (one in 10,000) at low, preventive doses; these reactions are more frequent with higher dosages used in treatment of diagnosed malaria. Travelers considering taking Lariam for the first time should take four (4) weekly test doses while still at home to see if any side effects occur. An alternative may be substituted should side effects occur. Mefloquine is not recommended for use by travelers with a known hypersensitivity to mefloquine, travelers with heart conduction abnormalities, travelers involved in tasks requiring fine coordination and spatial discrimination (such as airline pilots or scuba divers), travelers with a history of epilepsy or psychosis and travelers who will be at an altitude above 10,000 during their trip. Studies to date confirm that mefloquine is well tolerated in 95% of travelers when taken weekly; however, those who may have a severe adverse reaction should consult their physician and the reactions should be reported to Malaria Branch, CDC, telephone (404) 488-4046. Beware of counterfeit drugs purchased outside the U.S.

Doxycycline may cause photosensitivity (sun sensitivity or an exaggerated sunburn reaction). The risk of such a reaction can be minimized by avoiding prolonged direct exposure to the sun and using sunscreens that absorb long-wave ultraviolet (UVA) radiation. Doxycycline use is theoretically associated with an increased frequency of vaginitis. Esophagitis causing nausea, heartburn or abdominal pain, may occur and may be minimized by taking the drug with a meal followed by two large glasses of water, and not lying down within several hours after taking a dose. Test doses may be taken before departure. Doxycycline must not be used in pregnancy or in children under age 8 years.

Malarone may be used in travelers weighing over 24 pounds. The main adverse effect the possibility of interaction with some prescription medications. Your list of medications taken each day should be evaluated for this problem if you are going to use Malarone. Malarone should not be used in pregnancy.

TREATMENT OF MALARIA The malignant form of malaria may be rapidly fatal. If fever (consider taking a thermometer) indicating possible malaria occurs while overseas, medical care should be sought immediately. If it is known that significant time will be spent distant from medical care (over 12-24 hour transport time), and Malarone is not being used as the preventive medication, you may wish to carry treatment doses of Malarone (4 pills daily for 3 days). In this situation, medical advice should be sought after taking Malarone since other medical care may be needed.

PREVENTION OF RELAPSES Malaria parasites can persist in the liver and cause relapses for many years after chloroquine, mefloquine or doxycycline are discontinued. Travelers to malarious areas should know that if fever occurs after leaving a malarious area, they should report their travel history and the possibility of malaria to a physician as soon as possible.

Primaquine decreases the risk of relapses by acting against the liver stages of malaria. Even if a traveler feels well, this drug should be given after the traveler has left a malarious area in which there have been numerous mosquito bites. Primaquine is usually taken during the last 2 weeks of the period of the primary preventive medication (either chloroquine, mefloquine or doxycycline) after exposure in malaria-endemic areas.

For considerations for children, pregnancy and breast feeding, see more complete information in Health Information for International Travel published by the CDC. Detailed recommendations for the prevention of malaria are available 24 hours a day by calling the CDC Malaria Hotline at (404) 332-4555.
(From Health Information for International Travel, Centers for Disease Control)

Options For Prevention Of Chloroquine-Resistant Malaria

* being in the malarious area