Definition

Malaria is a disease passed through the blood. It is caused by a parasite. The parasite is typically passed to humans through the bite of an infected mosquito.

Causes

Malaria is caused by one of the following four types of parasites:

  • Plasmodium falciparum
  • Plasmodium vivax
  • Plasmodium ovale
  • Plasmodium malariae

An Anopheles mosquito becomes infected when it bites someone with malaria. Another bite will pass the malaria to a new person.

Malaria can also be passed from a mother to her unborn child. It can also be passed through a blood transfusion from an infected donor.

Malaria Cycle

Nucleus factsheet image
© 2009 Nucleus Medical Art, Inc.

Plasmodium falciparum is by far the most dangerous of the forms of malaria. In most areas it is also the most common form.

Risk Factors

Risk factors that increase your chance of malaria include:

  • Living in or traveling to hot, humid climates where Anopheles mosquitoes are prevalent
  • Failing to use DEET-containing insect repellents when outdoors
  • Failing to use mosquito netting (especially netting treated with permethrin) while sleeping
  • Failing to use medications to prevent malaria infection
  • Geography: Africa, Asia, and Latin America:
    • Malaria occur regularly among tourists who fail to follow recommended precautions
    • The majority of fatal cases of malaria seem to be acquired by tourists visiting game parks and other rural areas in east Africa

Symptoms

Once inside the bloodstream, parasites travel to the liver. There they and multiply (hepatic phase). During this phase, the infected person has no symptoms.

After several days, the parasites' offspring are released into the bloodstream. There they infect red blood cells. Within 48 hours, the infected red blood cells burst. The parasites infect more red blood cells. This process leads to:

  • Recurrent fevers (as high as 106 degrees F)
  • Chills
  • Diffuse muscles aches
  • Headaches
  • Nausea and/or vomiting
  • Diarrhea
  • Anemia
  • Jaundice (yellow coloring of the skin or eyes)
Without treatment, the cycle of red blood cell destruction and fever will continue. This can lead to death.

Symptoms usually begin within 10 days to four weeks after being bitten by an infected mosquito. P. malariae may not produce symptoms for a year or more. P. falciparum infections tend to cause more severe symptoms. They are associated with higher death rates.

Diagnosis

The doctor will ask about your symptoms, medical history. The doctor will also ask about your travel history. A physical exam will be done. You will have:

  • Blood tests—to analyze your blood for parasites

Treatment

Prescription drugs are used to treat malaria. They kill the parasites. Choice of antimalarial agent depends on:

  • The type of parasite
  • Severity and stage of infection

The following medications are used alone or in combination:

*Commonly used to treat resistant strains of P. falciparum .

Prevention

To reduce your chance of getting malaria when in an area where malaria is prevalent:

  • Take antimalaria medication prior to, during, and after travel. Follow your doctor's instructions. Take medication exactly as prescribed.
  • Use DEET insect repellent when outside. It should be at least 30%-35%.
  • Use proper mosquito netting at night.
  • Use flying insect spray in non air-conditioned rooms while sleeping.
  • Wear clothing that covers as much skin as possible.
  • Avoid being outdoors from dusk to dawn. This is when mosquitoes are most prevalent.
  • Seek medical care immediately for any illness with high fever.