Malaria

Malaria is a serious and sometimes fatal tropical disease. Four kinds of malaria can infect humans: Plasmodium falciparum, P. vivax, P. ovale, and P. malariae. Infection with P. falciparum, if not promptly and correctly treated, can be fatal in as little as one or two days.

Competent advice from an up-to-date source, such as the tropical diseases department or travel clinic, is important.

Malaria is transmitted when an infected mosquito bites a human. The mosquitoes that can carry Plasmodium parasites are mostly active during dusk and dawn as well as at night. The best way to avoid infection is not getting bitten in the first place.

As stated by the CDC, malaria is transmitted in large areas of Central and South America, the island of Hispaniola (which includes Haiti and the Dominican Republic), Africa, Asia (including South, Southeast Asia and the Middle East), and a few areas of Melanesia.

In general, the risk of contracting malaria is higher in rural areas and lower in urban areas. Often there is also a correlation to the mosquito population, with the rainy season creating stagnant pools of water where mosquitoes can breed. Many cities in tropical areas were founded at elevations where mosquitoes are or rather were rare; however, with climate change, this is beginning to change in some places.

Symptoms of malaria can mimic the flu, with an infected person developing fever, headache, and vomiting usually within 10 to 15 days after the mosquito bite. This means that you may become sick when you are back at home.

Malaria is potentially life-threatening, and requires immediate treatment. There are two moderately successful vaccines for young children as of 2026. In travelers methods of prevention are avoiding mosquito bites and using preventative medication. Some drugs are not effective for all areas. If a person who has visited a malaria risk zone contracts a fever within one year, their physician should be informed of the possibility of malaria. Physicians in many areas of the world rarely, if ever, see malaria and may need to be reminded of the possibility. The standard laboratory test for malaria is a thick and thin blood smear on a glass slide viewed under the microscope. Self-test kits are unreliable.

The best prevention against malaria is to avoiding being bitten by mosquitoes, particularly at night when the Anopheles mosquitoes are active. Useful measures include using DEET and wearing long pants and shirts. Not every accommodation offer mosquito nets, so best bring your own net. Air-conditioning and fans can also help indoors.

Medications for prevention must be taken before, during, and after travelling to a malaria-risk zone. Anti-malarial drugs are highly effective. Different drugs are recommended for travel to different areas due to malarial strain resistance. Talk to a doctor or verify the information with a reliable source. As with all drugs, anti-malarials may cause side-effects. Seldom will malaria be the sole health concern, and the physician will need to assess all the health risks the traveller will face. Obtain medications from a reliable source, either at home before you leave or from a reliable chemist/pharmacist in a high-end or tourist area. Sometimes, the pills sold might be fakes.

Mefloquine can have serious psychological and neurological side effects (anxiety, headaches, insomnia, dizziness) that are significant in about 11–17% of travelers. Pregnant women should be especially careful, as some anti-malarials must not be taken during pregnancy. Malaria during pregnancy is usually more severe, and it's always considered to be a serious emergency.

As with most methods of prevention, anti-malarials are not 100% effective; however, when taken as directed, the most common (e.g. doxycycline, Malarone) are about 98–99% effective. The choice should be made carefully with one's physician, taking into account resistance in the traveller's destination; possible side effects, interactions, and contra-indications; and finally the preferred frequency per dose (daily, weekly)

See Mosquitoes for more detailed advice.

The most common anti-malarials include:

• Doxycycline is highly effective and generally inexpensive. Possible disadvantages include sun sensitivity (sunburning easier), nausea, and stomach or esophageal pain (if one does not eat taking the medication)
• Mefloquine (Lariam among others) is highly effective, has a simple weekly dose and can be taken for extended periods. It does have a number of contra-indications, and has rare but potentially severe neurological side effects. More common side effects include nausea, stomach cramps and lucid dreams. Not to be used if you plan on scuba diving or high-altitude climbing. Your doctor may advise starting using it several weeks before departure, in order to check for possible side effects. There are resistant mosquitoes in Southeast Asia, and West and East Africa.
• Atovaquone/proguanil (Malarone) is highly effective, has a low risk of side effects, and only needs to be taken for one week after leaving the risk area; however it is expensive.
• Chloroquine (Daramal, Nivaquine, or Promal) in combination with proguanil (Paludrine) is generally well tolerated. Problems include widespread resistance and people having difficulty adhering to the prescribed regime.

There is debate over whether pre-travel malaria prevention is started early enough. For example, mefloquine is normally taken one week prior to travel. Some feel this is inadequate if the person is exposed to malaria shortly upon arrival. Those who have concerns may wish to discuss with their physician the option of doubling the time period (not the dosage) that their malaria prevention will be taken prior to travel. In addition to providing better protection, there will be more time to switch to another anti-malaria medication, if necessary.

Acetylsalicylic acid (Aspirin) should not be taken to treat fever when malaria or dengue fever is a possibility; continuing daily low-dose 81mg aspirin during and after third-world travel should be discussed with your physician. Acetaminophen (paracetamol) and ibuprofen are considered safer alternatives. Malaria, dengue fever, and typhoid fever all tend to have somewhat similar symptoms initially.

Travel to rural areas always involves more potential exposure to malaria than in the larger cities. (This is in contrast to dengue fever where cities present the greater risk.) For example, the capital cities of the Philippines, Thailand and Sri Lanka are essentially malaria-free. However, malaria is present in many other places (especially rural areas) of these countries. By contrast, in West Africa, Ghana and Nigeria have malaria throughout the entire country. However, the risk is much lower in the larger cities. Always use up-to-date information as to whether malaria is present in the areas you will be visiting, and what prophylactic resistance occurs locally. A small map of the world (above) cannot show small pockets of malaria-free zones (which are likely to be prime tourist areas and/or larger cities). Conversely, sometimes malaria spreads into new territory—especially higher elevations near endemic zones.

Travellers should never assume that their choice of malaria prophylaxis is available in the country that they will be visiting. Many developing countries stock only chloroquine and possibly doxycycline and there is also a risk of buying fake drugs. Quinine (a natural drug, and known for centuries) might also be available, but is not recommended as a prophylactic anti-malarial. Resistance to it is extremely common.

• WHO - Malaria. World wide information on malaria from the World Health Organization.
• CDC Yellow Book 2024 - Malaria
• MAP (Malaria Atlas Project)^{[dead link]}
• MARA (Mapping Malaria Risk in Africa)^{[dead link]}, a malaria atlas for Africa. Requires registration.
• South African Department of Health^{[dead link]}
• The National Health Service in Scotland publishes maps showing malarial hotspots^{[dead link]}
• IAMAT (International Association for Medical Assistance to Travellers)^{[dead link]} Malaria information, white paper, and risk chart for travellers
• Our World in Data - Incidence of malaria by country

• Pests