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The Manual's Editorial Staff

Reviewed/Revised Jul 2023
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What is malaria?

Malaria is an infection by a microscopic parasite called Plasmodium.

  • Malaria is spread by mosquitoes

  • Every year millions of people around the world get malaria

  • Almost half a million people die from malaria every year, mostly children

  • Malaria causes fever and chills

  • It's diagnosed with a blood test

  • Several medicines treat malaria, but the parasites are becoming resistant to the medicines

Malaria used to occur almost everywhere in the world. Now it's mainly in warmer parts of the world such as:

  • South America

  • Central America and islands in the Caribbean

  • Africa

  • India and other parts of South Asia

  • Middle East

What causes malaria?

There are 5 species of the malaria parasite that affect people.

  • Malaria parasites live in the red blood cells of infected people

  • When mosquitoes bite an infected person, they pick up the parasite

  • The next person the mosquitoes bite can get infected

Malaria parasites first go to your liver to mature and reproduce. Then the parasites go into your blood and reproduce inside your red blood cells.

The most dangerous form of malaria is called falciparum malaria. Falciparum malaria is especially dangerous because the infected red blood cells can clog up tiny blood vessels and cause organ damage. They may damage your brain, kidney, lungs, and other organs. Other forms of malaria don't do this.

What are the symptoms of malaria?

You may not get symptoms for several weeks or longer after being bitten by an infected mosquito. Then you get:

  • High fever

  • Shaking chills (very bad shivering)

  • Headache, muscle aches, and feeling very sick

The fever and chills come and go every couple of days. As the infection continues, you may get:

Falciparum malaria also causes other symptoms depending on what organs are affected:

Pregnant women may have a miscarriage, or their baby may be infected.

How can doctors tell if I have malaria?

Doctors do:

  • Blood tests

There are 2 types of blood tests: (1) rapid tests using blood placed on a card and (2) tests to look at the blood under a microscope. Doctors often do both types of tests.

How do doctors treat malaria?

Medicines for malaria depend on which species you have and where you got it. In some parts of the world, malaria parasites are resistant to many malaria medicines.

In some remote areas where malaria is common, malaria medicines sold by local pharmacies may be counterfeit. If you're traveling to a high-risk area, your doctor may have you bring along malaria medicines just in case you get infected.

How can I prevent malaria?

On October 6, 2021, the World Health Organization (WHO) recommended widespread use of a malaria vaccine among children living in sub-Saharan Africa and in other regions with moderate to high Plasmodium falciparum malaria transmission.

If you visit or live in an area that has malaria, you need to:

  • Do things to avoid mosquito bites

  • Take preventive medicine to kill malaria parasites

To avoid mosquito bites:

  • Sleep under a mosquito net that is coated with the insecticide permethrin

  • Apply mosquito repellents containing DEET (diethyltoluamide)

  • Wear long pants and long-sleeved shirts, particularly between dusk and dawn

  • If you're going to be exposed to a lot of mosquitoes, wear clothing that has been coated with permethrin

People who live in areas with malaria often spray insecticide in their homes and outbuildings, place screens on their doors and windows, and clean up any standing water (like in old tires, flower pots, or puddles), which is where mosquitoes like to breed.

You can take medicine to prevent malaria. Several different medicines are available. Your doctor can advise which one is right for where you're traveling and for your health conditions. You'll need to start taking the medicine before you get to the area with malaria.

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