الأربعاء، 8 يونيو 2011

Malaria


Overview, Causes, & Risk Factors

Malaria is an infection marked by fever and shaking chills. Four different species of the Plasmodium parasite cause malaria.
What is going on in the body?
Malaria occurs mainly in the tropical areas of the world, including Africa, Asia, and Central and South America. Humans acquire malaria through the bite of a mosquito. There are 4 species of Plasmodium that cause infection.
When an infected mosquito bites a person, the parasite travels through the bloodstream to the liver. The parasite multiplies in the liver. Then it goes back into the bloodstream and attacks the red blood cells. As the red blood cells are destroyed, symptoms begin in the body.
What are the causes and risks of the infection?
The Plasmodium parasite causes infection. The bite of the anopheles mosquito transmits the parasite from person to person. When a mosquito bites a person who has malaria, the parasite multiplies in the mosquito. If the mosquito then bites another person, it can inject the parasite into another person. The infection can also be spread from an infected pregnant woman to the fetus across the placenta.

Symptoms & Signs

What are the signs and symptoms of the infection?
Common symptoms of malaria are as follows:
  • fever, which may recur every 48 to 72 hours

  • shaking chills

  • excessive sweating

  • headache

  • nausea and vomiting

  • diarrhea

  • rapid breathing


    • Infection in a newborn baby can cause the following:
  • fever

  • poor feeding

  • irritability

  • decreased activity

    • Diagnosis & Tests

    How is the infection diagnosed?
    A healthcare provider may suspect malaria after examining the person. The parasite causing the malaria can be determined by examining a blood smear under a microscope. The best time to obtain these blood samples is during a fever. A chest X-ray may be done if lung damage is suspected. A complete blood count, or CBC, may be ordered to look for low numbers of red blood cells and signs of infection.

    Prevention & Expectations

    What can be done to prevent the infection?
    People who travel to an area where malaria exists should take antimalarial medications. The exact medication depends on the area and the type of Plasmodium there. Travelers can also help prevent mosquito bites by doing the following:
  • wearing protective clothing

  • wearing light clothing at night

  • avoiding the outdoors at night

  • using mosquito netting while sleeping

  • using insect repellents


    • What are the long-term effects of the infection?
    Long-term effects that may result if malaria is untreated are as follows:
  • very low blood count

  • respiratory failure

  • kidney failure

  • jaundice, or yellowing of the skin

  • low blood pressure


    • Infection in the central nervous system may cause the following:
  • confusion

  • decreased consciousness

  • seizures

  • possibly death


    • Some types of Plasmodium can cause chronic infection in the liver. This can cause a relapse many years after the first infection.
    What are the risks to others?
    Malaria is not spread directly from person to person. But if a mosquito bites an infected person, the mosquito can spread the disease to the next person it bites. Malaria may pass through the placenta of a pregnant woman and infect her fetus.

    Treatment & Monitoring

    What are the treatments for the infection?
    Antimalarial medications or antibiotics may be used to treat malaria. The choice of antibiotic depends on the following factors:
  • the species of malaria, and whether it is likely to be resistant to medications

  • the age of the infected person

  • the extent of symptoms


    • Medications commonly used to treat malaria include:
  • quinine sulfate

  • a combination of atovaquone and proguanil

  • mefloquine


    • Hospitalization and intravenous medications may also be necessary.
    What are the side effects of the treatments?
    Medications used to treat malaria may cause stomach upset or allergic reactions.
    What happens after treatment for the infection?
    For mild symptoms, bed rest, adequate nutrition, and medications may be enough. Recovery from more serious complications of malaria may take more time.
    How is the infection monitored?
    Any new or worsening symptoms should be reported to the healthcare provider.

    Attribution

    Author:Danielle Zerr, MD
    Date Written:
    Editor:Ballenberg, Sally, BS
    Edit Date:01/31/01
    Reviewer:Eileen McLaughlin, RN, BSN
    Date Reviewed:07/13/01
    Sources
    Harrison's Principles of Internal Medicine, 1998, Fauci et al. Complete Guide to Symptoms, Illness, and Surgery, 2000, Griffith. www.cdc.gov/travel/malinfo.htm.
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