Definition | Causes | Risk Factors | Symptoms | Diagnosis | Treatment | Prevention

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

Malaria Cycle

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Plasmodium falciparum is by far the most dangerous form 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 medicines to prevent malaria infection
  • Geography: Africa, Asia, and Latin America:
    • Malaria occurs 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 multiply (hepatic phase). During this phase, the infected person has no symptoms.

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

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 with higher death rates.

Diagnosis

The doctor will ask about your symptoms, medical history, and travel history. A physical exam will be done. You will have blood tests done.

Treatment

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

  • Type of parasite
  • Severity and stage of infection

The following medications are used alone or in combination:

  • Chloroquine —In many parts of the world, P. falciparum is resistant to this drug.
  • Mefloquine
  • Doxycycline
  • Clindamycin
  • Malarone
  • Quinidine
  • Quinine
  • Artemisinin
  • Combination of pyrimethamine and sulfadoxine ( Fansidar )
  • Primaquine (for hepatic phase of P. vivax and P. ovale)

Many of these medicines are 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 medicine prior to, during, and after travel. Follow your doctor's instructions.
  • Use DEET insect repellent when outside. It should be at least 30%-35%.
  • Use proper mosquito netting at night.
  • Do not rely on electronic mosquito repellents, which are supposed to repel mosquitoes by emitting a sound. These devices do not prevent mosquito bites.
  • 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 right away for any illness with high fever.