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Malaria

What is malaria?

Malaria is the most significant parasitic disease threat you will face in most tropical and subtropical countries. It is a microscopic blood- borne parasite transmitted to humans by the bites of infected mosquitoes.  There are 300 to 500 million cases a year of malaria worldwide —approximately 1000 a year are reported in U.S. travelers. 

Symptoms can include: fever and flu-like symptoms, chills, generalized muscle aches and pains, tiredness, headache, abdominal pain, and even diarrhea.  Symptoms usually begin 1 to 2 weeks after an infected bite, but onset can be as late as 4 or more weeks afterwards in some cases.  If left untreated, malaria can cause anemia, jaundice, kidney failure, coma, and death. 

Travelers can decrease the risk of malaria by taking certain drugs to prevent a malaria attack (malaria chemoprophylaxis) and by using measures to prevent mosquito bites.  However, in spite of all precautions, travelers occasionally might become infected with malaria.  Therefore, while traveling and up to five years after returning home, travelers should seek medical evaluation for any flu-like illness accompanied by fever.

If you have an extended period of travel or experience numerous mosquito bites in a malaria area, you may need additional anti-malarial medication after your return, to eradicate a possible asymptomatic incubating malaria infection.  If this situation applies to you, continue your prescribed malaria chemo-prophylaxis medication and seek care within two weeks after your return.

You are excluded from blood donation for 1 year after being in a malarious area.

Prevention

Travelers should limit their time outdoors in rural tropical areas between dusk and dawn, when the mosquitoes transmitting malaria are most likely to bite.  When outdoors, prevent mosquito bites by staying in screened areas as much as possible; wearing protective clothing that covers arms and legs; using an insect repellent on exposed skin areas when outdoors; and using a mosquito net where you sleep.  For more detailed information on procedures and products to prevent mosquito and other insect bites, see our health information article or brochure Avoiding Insects.

Drugs Against Malaria

No anti-malaria drug is 100% effective and drug resistant strains of malaria are being reported throughout the world.  Selection of the most effective regimen depends on itinerary, whether drug resistant malaria is reported at destination areas, age, health, allergies, and other factors. One of the following options may be selected.

1. Chloroquine Phosphate  (Aralen®)

Adult dosage: 500 mg orally once/week for use in areas with chloroquine-sensitive Plasmodium falciparum malaria. Take weekly dose starting 1 week before entering a malaria area, each week while there, and for 4 weeks after leaving the area.

Notes on Chloroquine:

  • Drug interactions can occur with Kaopectate®, methotrexate, metronidazole (Flagyl®), Phenergan®, and cimetidine.
  • Chloroquine can be used with caution in persons who have psoriasis, porphyria, or liver dysfunction, but not in those with retinal degeneration.
  • Chloroquine can decrease the effectiveness of the rabies vaccine given by intra-dermal administration, if taken sooner than 1 week following the last vaccine dose.
  • Chloroquine is considered safe in pregnancy.

2. Hydroxychloroquine Sulfate (Plaquenil®)

Adult dosage: 400 mg (2x 200 mg) orally once/ week—an alternative to chloroquine.

Notes on Hydroxychloroquine:

  • Drug interactions can  occur with  digoxin and rifampin and possibly with the drugs listed above under Chloroquine.
  • Hydroxychlorquine can be used with caution in persons who have psoriasis, porphyria, or liver dysfunction, but not in those with retinal degeneration.
  • Hydroxychloroquine can decrease the effectiveness of rabies vaccine given by intra-dermal administration, if taken sooner than 1 week following the last dose.

3. Mefloquine (Lariam®)

This drug is recommended for travelers going to areas of chloroquine-resistant Plasmodium falciparum malaria.

Adult dosage: Take 1 tablet, 250 mg, once a week 1 to 2 weeks before entering the risk area, then weekly during travel and for 4 weeks after leaving the malaria risk area. 

Notes on Mefloquine:

  • Especially in Africa, you will hear tales of how toxic mefloquine is; it is still the very best anti-malarial where there is chloroquine resistance
  • Not recommended for persons with epilepsy and other seizure disorders; with severe psychiatric disorders; or with cardiac conduction abnormalities.
  • Drug interactions — with certain seizure medications.
  • Minor side effects tend to be transient and self-limited: nausea and gastrointestinal disturbances; insomnia, vivid dreams, or nightmares; dizziness, lightheadedness, headache, visual disturbance, or other neuropsychiatric symptoms.
  • Mefloquine should be discontinued if unexplained anxiety, depression, restlessness or confusion is noted.
  • Mefloquine should not usually be taken for two months prior to pregnancy, nor during the first three months of pregnancy.
  • How to take: with at least 8 oz. of water, soon after a meal. Side effects may be reduced by avoiding alcohol and the antibiotics Cipro® and Levaquin® within 12 hours of the dose or by splitting the pill (with a pill splitter available at travel pharmacies) and taking 1/2 a pill twice a week. The risk with splitting the dose is in forgetting to take both 1/2's each week, which is essential.
  • Contraindications: any history of seizure disorder, psychosis, major depression, other significant psychiatric conditions, serious liver dysfunction or a cardiac rhythm or conduction disturbance.
  • Presumptive self treatment: In special circumstances mefloquine is used on a presumptive treatment basis for travelers who have symptoms compatible with malaria and cannot be medically evaluated within 24 hours. Discuss this option with your travel health consultant.

4. Doxycycline

Used for patients with intolerance to other antimalarials.

Adult dosage: Take 1 (100mg) tablet daily with evening meal starting 2 days before entering malarious area, each day while in the area and daily for an additional 4 weeks after leaving. Missing even one day's pill can result in malaria.

Notes on Doxycycline:

  • Doxycycline is not to be used by pregnant women or children under 9 years of age.
  • Due to increased sensitivity to the sun, wear a   sunscreen with a high SPF that covers both UVA and UVB.
  • Other potential side effects: vaginal yeast infections; erosion of esophagus if taken immediately before reclining without adequate liquids.
  • Pepto-Bismol® interferes with doxycycline absorption.

Treatment

If you have any of the aforementioned symptoms during or up to 3 years after leaving a malarious area, seek medical counseling. If a fever develops within 3 months after possible exposure, immediately seek medical help. Malaria can be treated if caught early enough, but delay in appropriate therapy can have serious or fatal consequences.