What Is Malaria?

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Malaria is an infection caused by a parasite that almost always is transmitted by mosquitoes. What happens if you get malaria is that you usually get sick. The first symptoms of malaria may appear anywhere from within one week after infection to within one year or more.

Malaria is rare in the United States, where only about 2,000 cases are reported each year. By contrast, there are more than 249 million cases of malaria around the globe annually, and more than 608,000 deaths are caused by the infection.

When someone in the U.S. comes down with malaria, it's usually because they were infected while visiting a region of the world where the disease is common.

This article explains the symptoms of malaria and its causes. It covers how malaria is diagnosed and what can be done to not only cure malaria but also prevent it.

Malaria Prevention Tips
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What Happens if You Get Malaria?

Most symptoms of malaria are the result of toxins that the parasite produces when it invades red blood cells. These toxins can cause anemia and, in many cases, blockages in small blood vessels throughout the body.

There are five different species of parasites that can cause malaria in humans. The one that is most deadly to humans is Plasmodium falciparum. P. falciparum is mainly found on the African content. If untreated, infections with this parasite can progress to severe illness and death within 24 hours.

P. vivax also poses a great threat and is found in most countries outside of sub-Saharan Africa. The other three malaria species that can infect humans are P. malariae, P. ovale, and P. knowlesi.

The symptoms of malaria may occur within a week after the infection or not until after one year or more. Symptoms include:

  • Fever and flu-like illnesses
  • Chills
  • Headache, muscle aches, and tiredness
  • Nausea, vomiting, and diarrhea

Malaria is also characterized by cycles of fever that last from six to 24 hours, alternating with chills, shaking, and sweating. These cyclic symptoms usually are the ones that are likely to tip off a healthcare provider that a patient may have malaria.

If malaria goes untreated, it can affect different organs of the body, potentially leading to severe complications and death. Plasmodium falciparum malaria, caused by the most dangerous parasite, can lead to death if not treated within the first 24 hours.

Malaria can cause serious effects in as many as 60% of people who become infected, especially those with immune system deficiencies. People who are infected while pregnant may become very ill and can have babies with birth defects or a malarial infection.

How long can you live with malaria untreated?

Complications that are associated with malaria include:

  • Anemia
  • Thrombocytopenia (a condition in which a low blood platelet count interferes with normal blood clotting)
  • Kidney problems
  • Cerebral malaria (not common but can be devastating or even fatal)
  • Coma, loss of consciousness, or death

Causes of Malaria

There are four species of the Plasmodium parasite, the specific organism that causes malaria. The most common way to become infected is by being bitten by a female Anopheles mosquito that has picked up the parasite by biting someone else already infected.

Once the infective form of a Plasmodium parasite enters the body, it hunkers down in the liver, reproduces, and then enters the red blood cells. At this point, symptoms of malaria will begin to appear.

Besides direct infection from a mosquito bite, it's possible for malaria to be transmitted via a blood transfusion, though it's very rare in the U.S. Babies sometimes acquire the parasite from their mothers before birth. People with immune system deficiencies, including women who are pregnant, are more likely to develop malaria after being bitten. 

Malaria is rare in the United States but is an ongoing problem in certain parts of the world with a tropical climate and a lot of still water where mosquitoes thrive. People who live in these regions, as well as visitors, are at high risk of becoming infected.

Diagnosing Malaria

The diagnosis of malaria can be delayed because the initial symptoms are often so vague and general that flu seems more likely than a parasitic infection. In addition, the lengthy incubation period means that characteristic symptoms of malaria may not appear for weeks or months after the mosquito bite took place.

Malaria can be diagnosed by different diagnostic tests. A blood smear microscopy examines a drop of blood under a microscope for the presence of malaria parasites.

Rapid diagnostic tests (RDTs) can test for antigens from malaria parasites. RDTs can deliver results in less than 15 minutes but aren't quite as good as a blood smear microscopy test. In the U.S., you need to see a healthcare provider for RDTs.

Another option is polymerase chain reaction (PCR) tests. These tests are extremely good at detecting malaria, but it takes longer to get the results. PCR tests can also tell you exactly what species of malaria parasite you have and detect mixed infections.

A non-invasive test such as computerized tomography (CT) or magnetic resonance imaging (MRI) of the brain is sometimes used if there's a possibility that malaria has spread to the brain.

Because some of the symptoms of malaria are similar to those of certain other conditions, diagnostic tests may be necessary to definitively differentiate malaria from illnesses. The tests can look for viral or bacterial infections, sepsis (a body-wide reaction to a bacterial bloodstream infection), and a sickle cell anemia crisis

Can Malaria Be Cured?

In general, malaria is curable if diagnosed and treated promptly. It’s important to start malaria treatment as soon as possible. 

Malaria is treated with prescription anti-parasitic medications, such as chloroquine and doxycycline. Additionally, a combination of home remedies and over-the-counter (OTC) drugs for managing symptoms can help while you are recovering.

Malaria drugs may have side effects. Doxycycline, which is sold under several brand names including Acticlate and Vibramycin, can make skin especially sensitive and prone to sunburn and also cause gastrointestinal problems, for example.

To alleviate symptoms such as fever, fatigue, and headache, get plenty of fluids and get enough rest. You can also manage your body temperature with blankets if you're chilled or ice packs if you're feverish. Taking OTC pain relievers and anti-fever medications can help.

Artemisinin drugs (artemether and artesunate) are also used to treat malaria. Intravenous (IV) artesunate is used to treat severe malaria in adults and children and should be followed by a complete treatment course of an appropriate oral antimalarial regimen.

The best treatment for uncomplicated Plasmodium falciparum malaria is artemisinin-based combination therapy (ACT). ACTs consist of two components—an artemisinin derivative and a drug from a different class.

Malaria Doctor Discussion Guide

Get our printable guide for your next doctor's appointment to help you ask the right questions.

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Preventing Malaria

Prevention and managing to avoid the infection altogether are key aspects of managing malaria.

What You Can Do

Here are some steps to take if you're planning to be in a country where there's a risk of malaria:

  • Pack protection: This means ample amounts of an effective bug spray that contains the insect repellent DEET.
  • Keep covered: Long sleeves and long pants can deter mosquitoes. If you're going to be sleeping where mosquitoes might gather at night, use a mosquito net.
  • Take prophylactic medications: You can check updated CDC guidelines to see if it's recommended for travelers who are going to the area where you are going.

Many of the medications used for malaria prevention are the same medications that are used for treatment. By taking prophylactic medication, you can avoid the whole process of becoming sick, and you won't have to worry about complications from the infection.

A hesitation people often have about taking preventive medications for malaria is the risk of side effects. Of particular concern are hallucinations and other psychiatric symptoms, which most often are associated with mefloquine.

Often side effects from malaria drugs can be avoided by taking other medications to prevent them. Discuss the pros and cons with your healthcare provider.


Malaria is a parasitic infection that is usually transmitted by mosquitoes. Although rare in the U.S., malaria is common in some other parts of the world. Symptoms of malaria are similar to those of the flu and can include fever, chills, muscle weakness, and more.

Diagnostic tests can detect the presence of the parasite. Prescription medications can both treat and prevent malaria. If you're traveling to a country where malaria is commonplace, talk to your healthcare provider and check the CDC recommendations to see if you need to take precautions, such as using insect repellent or taking prophylactic medication.

7 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Centers for Disease Control and Prevention. Malaria disease basics.

  2. World Health Organization. Malaria.

  3. Centers for Disease Control and Prevention. Symptoms of malaria.

  4. Centers for Disease Control and Prevention. Malaria transmission in the United States.

  5. Centers for Disease Control and Prevention. Testing for malaria.

  6. Centers for Disease Control and Prevention. About malaria: disease.

  7. Malaria Consortium. Artemisinin-based combination therapy.

Additional Reading

By Megan Coffee, MD
Megan Coffee, MD, PhD, is a clinician specializing in infectious disease research and an attending clinical assistant professor of medicine.