Find information on medical topics, symptoms, drugs, procedures, news and more, written in everyday language.

Malaria mu-!ler-E-u

By Richard D. Pearson, MD

Malaria is infection of red blood cells with one of five species of Plasmodium, a protozoan. Malaria causes fever, chills, sweating, an enlarged spleen, and anemia (due to the breakdown of infected red blood cells).

  • Usually, malaria is spread through the bite of an infected female mosquito.

  • People have a shaking chill, followed by a fever, and may have a headache, body aches, and nausea and feel tired.

  • One type of malaria causes serious symptoms, such as delirium, confusion, seizures, coma, severe breathing problems, kidney failure, and sometimes death.

  • Doctors diagnose the infection by identifying the protozoa in a sample of blood.

  • Eliminating mosquito breeding areas, killing larvae in standing water, preventing mosquito bites, and taking preventive drugs before traveling to affected areas can help.

  • Various antimalarial drugs are used to treat and to prevent infection (which drug is used depends on the malaria species causing the infection, the likelihood of drug resistance in the area where the infection was acquired, and the drug's side effects and cost).

Malaria is a protozoan infection that is spread by the bite of an infected female mosquito. Very rarely, the disease is transmitted from an infected mother to her fetus, through transfusion of contaminated blood, through transplantation of a contaminated organ, or through injection with a needle previously used by a person with malaria.

Although drugs and insecticides have made malaria rare in the United States and in most developed countries, the disease remains common and deadly in other areas. Worldwide, about 300 to 500 million people are infected with malaria, and about 655,000 deaths occur each year. Most of these deaths occur in children who are younger than 5 years and live in Africa. In the United States and other developed countries, malaria may occur in immigrants, visitors from the tropics, or North American travelers returning from tropical areas.

The cycle of malarial infection begins when a female mosquito bites a person with malaria. The mosquito ingests blood that contains reproductive cells of the parasite. Once inside the mosquito, the parasite reproduces, develops, and migrates to the mosquito’s salivary gland. When the mosquito bites another person, parasites are injected along with the mosquito’s saliva. Inside the newly infected person, the parasites move to the liver and multiply again. They typically mature over an average of 1 to 3 weeks, then leave the liver and invade the person’s red blood cells. The parasites multiply yet again inside the red blood cells, eventually causing the infected cells to rupture, releasing parasites to invade other red blood cells.

Did You Know...

  • About 300 to 500 million people throughout the world are infected with malaria, and each year, 655,000 people die.

  • Symptoms of malaria sometimes do not appear until years after the initial infection.

Resources In This Article

Drugs Mentioned In This Article

  • Generic Name
    Select Brand Names
  • No US brand name