Malaria is a parasitic infection of the blood, transmitted by night-biting mosquitoes. The parasite, Plasmodium, multiplies in the liver before infecting red blood cells. Symptoms include fever, chills, headache and vomiting, and can appear 10–15 days — or up to a year — after a mosquito bite. If not treated promptly, the severe form of the disease, caused by Plasmodium falciparum, can be rapidly fatal, especially in children and pregnant women.
Malaria risk is highest in sub-Saharan Africa, where P. falciparum predominates. Risk is much lower in Asia and South America, where the main species is Plasmodium vivax, which causes a less severe disease. However, P. vivax can lie dormant in the liver and cause a relapse much later.
What is the risk of malaria in Nepal?
Although malaria is endemic in Nepal, the risk for the average tourist or expatriate seems extremely low. We have not seen a single case of malaria acquired in Nepal in a traveler in the past 25 years. We believe there is no malaria risk in Kathmandu, Pokhara or the mountain trekking areas.
Malaria does exist in the southern belt of Nepal (the Terai), particularly in the west, and risk is highest in June, July and August. Most malaria in Nepal is vivax. The latest ward-level micro-stratification study by Nepal's Epidemiology and Disease Control Division (EDCD), in 2022, shows a declining trend in transmission. Lumbini, Karnali and Sudurpashchim provinces have the highest risk.
Chitwan, although it lies in the Terai, has a very low malaria risk. For short visits to Chitwan National Park — even in the monsoon — we recommend mosquito bite precautions and no malaria tablets.
How to prevent malaria
Malaria prevention means protection from mosquito bites, and taking medication to suppress the disease. Medications don't prevent the initial infection; they suppress or prevent the symptoms caused by parasites in the blood. Since malaria is spread by mosquito bites, preventing bites is just as important as taking tablets.
- Protect yourself from mosquito bites. Malaria-carrying mosquitoes bite at night, so avoid spending time outdoors without protection. Outdoors, cover up with long sleeves and long trousers. Use insect repellent (for example DEET 30% or picaridin 20%) on exposed skin — it's safe for children over 2 months old. Avoid putting DEET on hands, near the eyes or under clothing; apply it once a day and wash it off with soap and water once you're indoors. Use a fan, stay in a well-screened or air-conditioned room, or sleep under a permethrin-impregnated net.
- Consider taking malaria tablets. No malaria tablet is perfectly safe, so the risk of getting malaria must outweigh the risk of the medication. Weigh each option carefully and discuss with your nurse or doctor which tablet suits you best. We discourage carrying standby self-treatment, because so many common causes of fever in Nepal aren't malaria. Some medicines (such as antacids) reduce absorption of malaria tablets and shouldn't be taken at the same time.
- See a doctor immediately if you develop a fever — even if you've been taking malaria tablets while traveling in a malaria area. Some types of malaria can be rapidly fatal, and early diagnosis and treatment can be lifesaving.
Which medicines prevent malaria in Nepal?
As in many parts of the world where falciparum malaria exists, the parasites in Nepal have become resistant to chloroquine. For high-risk travel we advise one of four medicines: mefloquine, doxycycline, atovaquone/proguanil or tafenoquine.
Mefloquine (Lariam)
Mefloquine is highly effective and well tolerated by most people, but it causes troublesome side effects in up to 15% of users: trouble sleeping, dizziness, strange dreams, disorientation, confusion, mood swings, anxiety, depression, nausea, stomach upset, visual disturbances and palpitations. These can be very unpleasant but are reversible when the drug is stopped. They usually appear within the first few doses — which is why you start two weeks before travel. Don't take mefloquine on an empty stomach or within 24 hours of heavy drinking, or the side effects will be much worse. Taking it with dinner and plenty of water lowers the risk.
Mefloquine can be used in children and in the second and third trimesters of pregnancy. Women should use reliable contraception while taking it and for three months after the last dose. It isn't recommended for people with a personal or family history of psychiatric illness or seizures. If you develop unexplained anxiety, depression, hallucinations, severe nightmares or confusion, stop taking it and see a doctor. Mefloquine can affect tasks that need fine coordination, so it isn't recommended for pilots or scuba divers. Don't take quinine (for example, for leg cramps) at the same time. Taken weekly.
Atovaquone/proguanil (Malarone)
This tablet combines two antimalarials, atovaquone 250 mg and proguanil 100 mg. It works against both the liver and blood stages of the parasite, so it can be stopped one week after leaving the malaria area, and it suits short-term use. It can't be taken by children weighing less than 5 kg, by pregnant women, or by people with severe kidney disease.
It is extremely well tolerated. The most common side effects are nausea, vomiting and abdominal pain — but no more often than with a placebo. Taken daily.
Doxycycline
Doxycycline is an antibiotic that is as effective as mefloquine and atovaquone/proguanil against chloroquine-resistant falciparum malaria. It shouldn't be taken by children under 8, by pregnant or breastfeeding women, or by anyone allergic to tetracyclines. Some people burn more easily in the sun while taking it, so avoid too much sun (wear a hat and good sunblock).
Always take doxycycline with food and a full glass of water, to avoid irritating the esophagus (felt as pain or burning in the center of the chest). Don't take it just before bed or lying down. It's best to avoid antacids (such as Gelusil or Mylanta) while on doxycycline. It can cause vaginal itching or thrush; women prone to thrush after antibiotics should carry treatment just in case. Taken daily.
Tafenoquine (Arakoda, Krintafel)
A newer drug, licensed in the USA in 2018 for preventing and treating malaria. It is one of the most effective drugs for preventing P. vivax malaria, but it also prevents P. falciparum, and it's a good choice for shorter trips. Your G6PD level must be checked before taking tafenoquine. It isn't used in children, in pregnancy or breastfeeding, or in people with a history of psychosis.
How to take malaria tablets
| Medicine | Start | During | After leaving |
|---|---|---|---|
| Mefloquine | 2 weeks before | Weekly | 4 weeks |
| Doxycycline | 1 day before | Daily | 4 weeks |
| Atovaquone/proguanil (Malarone) | 1 day before | Daily | 1 week |
| Tafenoquine | 200 mg daily for 3 days before travel | Weekly | 1 week |
- With food. You'll have fewer side effects if you take your tablets with a meal and a large glass of water: eat some of your meal, take the tablets, then finish your meal.
- Same day each week. Take weekly tablets on the same day every week — for example, "Monday is malaria day."
- To the end. If you stop your tablets early, you may get malaria. These aren't like ordinary antibiotics: some take many weeks to kill all the parasites.
- Alcohol. Moderate drinking is fine. But heavy drinking within 24 hours of a dose of mefloquine is likely to provoke hallucinations, anxiety, behavior changes or even seizures.
If you forget a dose:
- Weekly tablets: take it the day you remember. If it's only one day late, carry on with your usual day; if it's several days late, take the following doses on the new day.
- Daily tablets: take it the day you remember and continue daily. Don't take extra tablets to make up for missed ones. If you've missed tablets you may get malaria — if a fever develops, see a doctor as soon as possible.
No tablet is 100% effective. Avoid mosquitoes, take your tablets regularly, and get every fever checked straight away.
Special situations
Children. Mefloquine can be used at any age and weight; doxycycline from age 8; atovaquone/proguanil (Malarone) from 5 kg (11 lb). Antimalarials are bitter and come only as tablets, but a pharmacist can crush the right dose into capsules, which can be opened and mixed with food. Pediatric doses aren't currently available at CIWEC: requests have been very rare, so we don't stock them.
Pregnancy. Malaria can be more severe in pregnant women and increases the risk of a poor pregnancy outcome. Since no prevention is completely effective, it's best to postpone or avoid travel to malaria areas if you're pregnant or may become pregnant during the trip. If the trip must go ahead, mefloquine is the only drug considered safe in the second and third trimesters; it may also be safe in the first.
Breastfeeding. Only very small amounts of chloroquine and mefloquine pass into breast milk, so breastfeeding women can use them for malaria prevention. The amount isn't harmful to the baby — but it isn't enough to protect the baby either. Doxycycline isn't recommended while breastfeeding, and atovaquone/proguanil isn't recommended if the baby weighs less than 5 kg.
Preventing vivax relapses (terminal prophylaxis). P. vivax can persist in the liver and cause a relapse up to 4 years after leaving a malaria area. Anti-relapse treatment with primaquine phosphate 30 mg daily for 2 weeks, or a single 300 mg dose of tafenoquine, lowers that risk by acting on the liver-stage parasites. Both drugs can cause hemolysis in people deficient in the enzyme glucose-6-phosphate dehydrogenase (G6PD), so G6PD levels must be checked first — we can test them at CIWEC.