Transmission and Symptoms

Malaria is a serious disease transmitted to humans by the bite of an infected female Anopheles mosquito. Symptoms may include fever and flu-like illness, including chills, headache, muscle aches, and fatigue. Malaria may cause anemia and jaundice. Plasmodium falciparum infections, if not immediately treated, may cause kidney failure, coma, and death. Malaria can often be prevented by using antimalarial drugs and by using personal protection measures to prevent mosquito bites. However, in spite of all protective measures, travelers may still develop malaria.

Malaria symptoms will occur at least 7 to 9 days after being bitten by an infected mosquito. Fever in the first week of travel in a malaria-risk area is unlikely to be malaria; however, any fever should be promptly evaluated.

Malaria is always a serious disease and may be a deadly illness. If you become ill with a fever or flu-like illness either while traveling in a malaria-risk area or after you return home (for up to 1 year), you should seek immediate medical attention and should tell the physician your travel history.

Malaria Risk by Country

Papua New Guinea: Risk in all areas lower than 1800 meters (5906 feet). Solomon Islands: Risk in all areas except for the southern province of Rennell and Bellona, the eastern province of Temotu, and the outer islands of Tikopia, Anuta, and Fatutaka.Vanuatu: Risk in all areas.

There is no risk of malaria in: Australia, Cook Island, Fiji, French Polynesia (Tahiti, Moorea, Bora-Bora, etc.), Kiribati, Marshall Islands, Micronesia, Nauru, New Caledonia, New Zealand, Niue, Northern Mariana Islands, Palau, Pitcairn, Samoa, Tokelau, Tonga, Tuvalu, U.S. Trust Territory of the Pacific Islands (Guam, American Samoa, Johnston Atoll, Wake Island, Midway Island), and Wallis & Futuna.

Prevention

All travelers to malaria-risk areas in the South Pacific, including infants, children, and former residents of the South Pacific, should take one of the following antimalarial drugs (listed alphabetically):

• atovaquone/proguanil,
• doxycycline,
• mefloquine,
• primaquine (in special circumstances; see below)

Atovaquone/proguanil is a fixed combination of two drugs, atovaquone and proguanil. In the United States, it is available as the brand name, Malarone™.

Directions for Use

• The adult dosage is 1 adult tablet (250mg atovaquone/100mg proguanil) once a day.
• Take the first dose of atovaquone/proguanil 1 to 2 days before travel to the malaria-risk area.
• Take atovaquone/proguanil once a day during travel in the malaria-risk area.
• Take atovaquone/proguanil once a day for 7 days after leaving the malaria-risk area.
• Take the dose at the same time each day with food or milk.

Atovaquone/proguanil Side Effects and Warnings
The most common side effects reported by travelers taking atovaquone/proguanil are abdominal pain, nausea, vomiting, and headache. Most travelers taking atovaquone/proguanil do not have side effects serious enough to stop taking the drug. Other antimalarial drugs are available if you cannot tolerate atovaquone/proguanil; see your health care provider.

Contraindications
The following travelers should NOT take atovaquone/proguanil (other antimalarial drugs are available; see your health care provider):

• children weighing less than 11 kilograms (25 pounds);
• pregnant women;
• women breast-feeding infants weighing less than 11 kilograms (25 pounds);
• patients with severe renal impairment;
• patients allergic to atovaquone or proguanil.

Doxycycline is related to the antibiotic tetracycline.

Directions for Use

• The adult dosage is 100 mg once a day.
• Take the first dose of doxycycline 1 or 2 days before arrival in the malaria-risk area.
• Take doxycycline once a day, at the same time each day, while in the malaria-risk area.
• Take doxycycline once a day for 4 weeks after leaving the malaria-risk area.

Doxycycline Side Effects and Warnings
The most common side effects reported by travelers taking doxycycline include sun sensitivity (sunburning faster than normal). To prevent sunburn, avoid midday sun, wear a high SPF sunblock, wear long-sleeved shirts, long pants, and a hat. Doxycycline may cause nausea and stomach pain. Always take the drug on a full stomach with a full glass of liquid. Do not lie down for 1 hour after taking the drug to prevent reflux of the drug (backing up into the esophagus).

Women who use doxycycline may develop a vaginal yeast infection. You may either take an over-the-counter yeast medication or have a prescription pill from your health care provider for use if vaginal itching or discharge develops.

Most travelers taking doxycycline do not have side effects serious enough to stop taking the drug. (Other antimalarial drugs are available if you cannot tolerate doxycycline; see your health care provider.)

Contraindications
The following travelers should NOT take doxycycline (other antimalarial drugs are available; see your health care provider):

• pregnant women;
• children under the age of 8 years;
• persons allergic to doxycycline or other tetracyclines.

Directions for Use

• The adult dosage is 250 mg salt (one tablet) once a week.
• Take the first dose of mefloquine 1 week before arrival in the malaria-risk area.
• Take mefloquine once a week, on the same day each week, while in the malaria-risk area.
• Take mefloquine once a week for 4 weeks after leaving the malaria-risk area.
• Mefloquine should be taken on a full stomach, for example, after a meal.

Mefloquine Side Effects and Warnings
The most common side effects reported by travelers taking mefloquine include headache, nausea, dizziness, difficulty sleeping, anxiety, vivid dreams, and visual disturbances.

Mefloquine has rarely been reported to cause serious side effects, such as seizures, depression, and psychosis. These serious side effects are more frequent with the higher doses used to treat malaria; fewer occurred at the weekly doses used to prevent malaria. Most travelers taking mefloquine do not have side effects serious enough to stop taking the drug. (Other antimalarial drugs are available if you cannot tolerate mefloquine; see your health care provider.)

Contraindications
Some travelers should NOT take mefloquine (other antimalarial drugs are available; see your health care provider):

• persons with active depression or a recent history of depression;
• persons with a history of psychosis, generalized anxiety disorder, schizophrenia, or other major psychiatric disorder;
• persons with a history of seizures (does not include the typical seizure caused by high fever in childhood);
• persons allergic to mefloquine;
• Mefloquine is not recommended for persons with cardiac conduction abnormalities (irregular heartbeat).

In certain circumstances when other antimalarial drugs cannot be used and in consultation with malaria experts, primaquine may be used to prevent malaria while the traveler is in the malaria-risk area (primary prophylaxis).

Directions for Use

Note: Travelers must be tested for G6PD deficiency (glucose-6-phosphate dehydrogenase) and have a documented G6PD level in the normal range before primaquine use.

• The adult dosage is 52.6mg salt (30mg base primaquine)/once a day.
• Take the drug 1-2 days before travel to the malaria-risk area.
• Take the drug once a day, at the same time each day, while in the malaria-risk area.
• Take the drug 7 days after leaving the malaria-risk area.

Primaquine Side Effects
The most common side effects reported by travelers taking primaquine include abdominal cramps, nausea, and vomiting.

Contraindications
Some travelers should not take primaquine (other antimalarial drugs are available; see your health care provider):

• persons with G6PD deficiency;
• pregnant women (the fetus may be G6PD deficient, even if the mother is in the normal range);
• women breast-feeding infants unless the infant has a documented normal G6PD level;
• persons allergic to primaquine.

Antimalarial Drugs Purchased Overseas

You should purchase your antimalarial drugs before travel. Drugs purchased overseas may not be manufactured according to United States standards and may not be effective. They also may be dangerous, contain counterfeit medications or contaminants, or be combinations of drugs that are not safe to use. Halofantrine (marketed as Halfan) is widely used overseas to treat malaria. CDC recommends that you do NOT use halofantrine because of serious heart-related side effects, including deaths. You should avoid using antimalarial drugs that are not recommended unless you have been diagnosed with life-threatening malaria and no other options are immediately available.

Protect Yourself from Mosquito Bites

Malaria is transmitted by the bite of an infected mosquito; these mosquitoes usually bite between dusk and dawn. If possible, remain indoors in a screened or air-conditioned area during the peak biting period. If out-of-doors, prevent mosquito bites by wearing long-sleeved shirts, long pants, and hats; apply insect repellent to exposed skin. Use insect repellents that contain DEET (diethylmethyltoluamide) for the best protection.

When using repellent with DEET, follow these precautions:

• Read and follow the directions and precautions on the product label.
• Use only when outdoors and wash skin with soap and water after coming indoors.
• Do not breathe in, swallow, or get into the eyes. (DEET is toxic if swallowed.) If using a spray product, apply DEET to your face by spraying your hands and rubbing the product carefully over the face, avoiding eyes and mouth.
• Do not put repellent on wounds or broken skin.
• Higher concentrations of DEET may have a longer repellent effect; however, concentrations over 50% provide no added protection.
• Timed-release DEET products may have a longer repellent effect than liquid products.
• DEET may be used on adults, children, and infants older than 2 months of age. Protect infants by using a carrier draped with mosquito netting with an elastic edge for a tight fit.
• Children under 10 years old should not apply insect repellent themselves. Do not apply to young children’s hands or around eyes and mouth.
• For details on how to protect yourself from insects and how to use repellents, see Protection against Mosquitoes and Other Arthropods.Travelers should also take a flying-insect spray on their trip to help clear rooms of mosquitoes. The product should contain a pyrethroid insecticide; these insecticides quickly kill flying insects, including mosquitoes.

If you are not staying in well-screened or air-conditioned rooms, you should take additional precautions, including sleeping under mosquito netting (bed nets). Bed nets sprayed with the insecticide permethrin are more effective; permethrin both repels and kills mosquitoes. In the United States, permethrin is available as a spray or liquid (e.g. Permanone) to treat clothes and bed nets. Bed nets may be purchased that have already been treated with permethrin. Permethrin or another insecticide, deltamethrin, may be purchased overseas to treat bed nets and clothes.

Additional Malaria Information

• Frequently Asked Questions
• Guidelines for diagnosis and treatment (for clinicians)
• Preventing Malaria in the Pregnant Woman (Information for the Public)
• Preventing Malaria in the Pregnant Woman (Information for Health Care Providers)
• Preventing Malaria in Infants and Children (Information for the Public)
• Preventing Malaria in Infants and Children (Information for Health Care Providers)
• Prescription Drugs for Preventing Malaria (Information for the Public)
• Prescription Drugs for Preventing Malaria (Information for Health Care Providers)

For information about other travel health risks, precautions, and vaccination recommendations, please see Health Information for Travelers to Australia and the South Pacific.

More Travel Health Information

• Download or order a copy of Health Information for International Travel (the "Yellow Book")