Malarial Fever

What is Malaria?

Malaria is an acute infectious disease transmitted by the bite of an infected mosquito. Single-celled parasites (plasmodia) enter the individual's bloodstream, and multiply in the liver for days or weeks before the disease becomes apparent. Eventually, the plasmodia infect red blood cells. Multiplication of the plasmodia in the red blood cells over the next few days causes the symptoms of malaria, which last twelve to twenty-four hours and then dissipate. The end of symptoms marks the beginning of a new life cycle for the plasmodia. In two to three days the symptoms reappear and the cycle continues. If untreated, these attacks can continue for years and may be fatal. Usually the body develops defenses against the organism and the disease subsides over time.

The disease is rare in the US, but is widespread in tropical and sub-tropical countries of the world.

How is it diagnosed?

History is usually of travel to tropical areas where malaria is common. Other risk factors include blood transfusions or use of non-sterile hypodermic needles that have come in contact with infected blood.

Symptoms of malaria include chills and shivering, followed by very high fever (up to 107 °F) and periods of profuse sweating. Symptoms last twelve to twenty-four hours and usually recur after a two to three day symptom-free interval. The individual may show signs of progressive fatigue and weariness. Muscle aches and pain usually accompany the signs of infection.

Physical exam may show uncontrollable shivering, high fever, nausea and vomiting, rapid and shallow breathing, or profuse sweating and a drop in body temperature. The spleen is often enlarged in individuals after multiple cycles of symptoms. Jaundice may or may not be present. Chronic infections may show evidence of kidney failure or coagulation disease (DIC) caused by the massive destruction of red blood cells and subsequent release of coagulation factors into the bloodstream. Symptoms of DIC include abnormal bleeding from anywhere in the body; tiny, red, pinpoint-like spots on the skin; vomiting of blood; bloody stools or urine; unexplained bruises and severe abdominal or back pain. Kidney failure may be marked by swelling of the ankles and tissues around the eyes; restricted passage of urine; shortness of breath; and accumulation of fluid in the lungs.

Occasionally plasmodia infect the adrenal glands causing a form of malaria called algid malaria. Symptoms include circulatory collapse, low blood pressure, hypothermia, rapid, thready pulse, and pale, clammy, cold skin. Abdominal pain, vomiting and diarrhea may be present. A postmortem examination will reveal congestion, hemorrhage and necrosis within the adrenal glands. When the plasmodia invade the brain, convulsions and coma may result.

Tests: Blood smears are examined for the presence of plasmodia. Extensive damage to red blood cells and anemia are common. Elevated white blood cell counts may be present. When possible, the species of plasmodia should be determined before treatment begins. Blood tests may be useful to detect antibodies to the plasmodia in non-endemic regions of the world. In high incidence regions of the tropics and sub-tropics, serum antibodies may be present in the absence of a current infection.

How is Malaria treated?

Malarial infections may be treated with any of a number of antimalarial drugs through chemotherapy. The choice of drugs depends upon the species of infecting organism, the number of parasites in the blood, and the resistance of the plasmodia to treatment with available drugs.

If extremely high fevers are present, fluids must be replenished and vigorous therapy is required to save the individual's life.

If the parasite level in the blood exceeds five-percent, death is imminent without rapid treatment. Exchange blood transfusions may reduce the parasitic burden, improve blood flow and improve the oxygen-carrying capacity of the blood.

When traveling to a high incidence area, antimalarial drugs may be used to prevent symptoms and limit the spread of new infections. Upon return, drug therapy is administered to clear the parasites from the liver.


Cleocin (Clindamycin), Doryx (Doxycycline), Sumycin (Tetracycline)


Rest in bed until fever and chills subside. Resume your normal activities gradually as symptoms improve.

What might complicate it?

Delays in diagnosis and subsequent therapy may result in complicated or fatal cases of malaria, particularly in the nonimmune host. Severe or fatal complications can occur at any time and are related to the plugging of vessels in internal organs. The nature and severity of complication often depend upon the parasitic burden in the bloodstream or organs. Failure of liver, kidney, spleen, brain or lungs may occur in untreated infections. Infection may be complicated by the presence of plasmodia that are resistant to the chosen or available chemotherapy. Side effects of antimalarial chemotherapy may lead to serious medical problems, even an occasional death.

Predicted outcome

Malaria is controllable when treated early with effective chemotherapy. The prognosis for most infections is good. If left untreated, malaria is life threatening. When the parasite level in the bloodstream is extremely high, complications of the disease will increase and therapy may require more aggressive action. The prognosis for these infections is less optimistic.


Malaria can mimic many other fever-producing diseases, such as influenza, gastroenteritis, amebic liver abscess, yellow fever, typhoid fever, tuberculosis, meningitis, encephalitis, and hepatitis.

Appropriate specialists

Infectious disease specialist, travel medicine specialist and gastroenterologist.

Notify your physician if

  • You or a family member has symptoms of malaria.
  • Weakness lasts for a prolonged time after an attack. This may indicate anemia.
  • Symptoms of malaria recur after treatment.

Last updated 25 June 2015


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