What Is Malaria?

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Malaria is an infection caused by a parasite that almost always is transmitted by mosquitoes. It's rare in the United States, where only about 1,700 cases are reported each year, according to the Centers for Disease Control and Prevention (CDC). By contrast, the World Health Organization reports that there are more than 200 million cases of malaria around the globe annually, and more than 400,000 deaths caused by the infection.

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

If you're traveling to a country where malaria is commonplace, you should talk to your doctor and check the CDC recommendations to see if you need to take precautions, such as using insect repellent or taking prophylactic medication.

Malaria Prevention Tips
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Malaria Symptoms

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 different species of parasites that can cause malaria. When it comes to symptoms, the type of parasite doesn't matter as much as the life-cycle stage it's in.

The most common symptoms of malaria include headache, fatigue, gastrointestinal problems (upset stomach, nausea, vomiting, and diarrhea), and muscle aches. 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 doctor that a patient may have malaria.

If malaria goes untreated, it can affect different organs of the body, potentially leading to severe complications.

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

Possible Complications

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

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 United States. 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.

Diagnosis

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 examining a drop of blood under a microscope for the presence of malaria parasites. Due to their improved accuracy, more endemic areas are employing rapid diagnostic tests (RDTs) that test for parasitic markers in place of microscopy or as a first step in diagnosing malaria. These tests can be done by staff with little medical training and do not require electricity to run.

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.

And 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 such as viral or bacterial infections, sepsis (a body-wide reaction to a bacterial bloodstream infection), and a sickle cell anemia crisis

Treatment

In general, malaria is curable if diagnosed and treated promptly. It’s important to start 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 be sure to get enough rest. You can also manage your body temperature with blankets if you're chilled or ice packs if you're feverish. And 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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Prevention

Prevention is a key aspect of managing malaria. If you can manage to avoid the infection altogether, there'll be no need for treatment.

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.
  • 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 doctor.

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6 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. About Malaria


  2. World Health Organization. World malaria report 2018


  3. Malaria. Frequently Asked Questions (FAQs)


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


  5. Centers for Disease Control and Prevention. Malaria - Disease.

  6. Malaria Consortium. Artemisinin-based combination therapy.

Additional Reading
  • Medline Plus . "Mefloquine." Mar 15, 2016.
  • Tan, Kathrine R, Magill, Alan J, Parise, Monica E, and Arguin, Paul M. "Doxycycline for Malaria Chemoprophylaxis and Treatment: Report from the CDC Expert Meeting on Malaria Chemoprophylaxis." Am J Trop Med Hyg. Par 5, 2011; 84(4): 517-531. DOI: 10.4269/ajtmh.2011.10-0285.