What Is Malaria and What Are the Symptoms?

Malaria is a serious and sometimes life-threatening tropical disease that spreads through parasites. It kills more than 445,000 people a year, many of them children in Africa.

Although malaria is almost wiped out in the United States, you can still get the disease when you travel to other parts of the world. The United States has about 1,700 malaria cases every year from immigrants and travelers returning from countries where malaria is more common.

These countries have warmer climates that are hot enough for the malaria parasites and the mosquitoes that carry them to thrive. These regions include sub-Saharan Africa, Southeast Asia, Latin America, and the Middle East.

Before you travel, check the CDC’s website to see whether your destination is a hotspot for malaria. You may have to take pills before, during, and after your trip to lower your chances of getting it.

Why Malaria Is Harmful

Malaria can cause high fever, chills, and flu-like symptoms that can be life-threatening when not treated quickly. The disease is caused by Plasmodium parasites, which are carried by Anophelesmosquitoes.

Only female mosquitoes spread the malaria parasites. When a mosquito bites a person who already has malaria, it sucks up the person’s blood, which contain the parasites. When the mosquito bites its next victim, it injects the parasites into that person. That’s how the disease is spread.

Once the parasites enter your body, they travel to your liver, where they multiply. They invade your red blood cells, which are important cells in your blood that carry oxygen. The parasites get inside them, lay their eggs, and multiply until the red blood cell bursts.

This releases more parasites into your bloodstream. As they attack more of your healthy red blood cells, this infection can make you feel very sick.

Types of Malaria

There are five species of Plasmodium parasites that affect humans. Two of them are considered the most dangerous:

  • P. falciparum. This is the most common malaria parasite in Africa, and it causes the most malaria-related deaths in the world. P. falciparum multiplies very quickly, causing severe blood loss and clogged blood vessels.
  • P. vivax . This is the malaria parasite most commonly found outside of sub-Saharan Africa, especially in Asia and Latin America. This species can lie dormant, then rise up to infect your blood months or years after the mosquito bite.



Symptoms for malaria usually start about 10 to 15 days after the infected mosquito bite. Here are some things to keep in mind, though:

  • Because the signs are so similar to cold or flu symptoms, it might be hard to tell what you have at first.
  • Malaria symptoms don’t always show up within 2 weeks, especially if it’s a P. vivax infection.
  • People who live in areas with lots of malaria cases may become partially immune after being exposed to it throughout their lives.

A blood test can confirm whether you have malaria. Along with high fever, shaking chills and sweating, symptoms can include:

Malaria can cause you to go into a coma.

Children with severe malaria may get anemia, a condition that happens when you lose too many red blood cells. They may also have trouble breathing. In rare cases they can get cerebral malaria, which causes brain damage from swelling.

When to Call a Doctor

Given how quickly malaria can become life-threatening, it’s important to get medical care as quickly as possible. Young children, infants, and pregnant women have an especially high chance for severe cases of malaria.

Seek care if you’re getting high fever while living in or traveling to an area that has high chance for malaria. You should still get medical help even if you see the symptoms many weeks, months or a year after your travel.

WebMD Medical Reference Reviewed by Jennifer Robinson, MD on December 22, 2018



CDC: “Malaria: Frequently Asked Questions,” “About Malaria.” “Where Malaria Occurs.” “Malaria Information and Prophylaxis, by Country.”

Medline Plus: “Malaria.”

World Health Organization: “Malaria.”

American Academy of Family Physicians: “Malaria.”

Medecins Sans Frontieres: “Malaria.”

Mayo Clinic: “Malaria.”

National Health Services: “Malaria.”

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