CAUSED BY FOUR species of the parasite Plasmodium (P. falciparum, P. vivax, P. ovale, and P. malariae), malaria is a serious, sometimes fatal, and often chronic disease that's usually transmitted by the bite of an infected female Anopheles mosquito. The parasites injected into a person during a mosquito bite multiply in the liver and red blood cells (RBCs). When infected RBCs burst, they release parasites into the bloodstream. In addition to transmission via mosquito bite, malaria can be transmitted congenitally from mother to fetus or through blood transfusions, organ transplants, or sharing contaminated needles or syringes.1
Malaria is relatively uncommon in the United States, with about 1,200 cases and 13 deaths reported each year. Most patients in the United States are immigrants and travelers returning from endemic areas, such as sub-Saharan Africa and South Asia. Worldwide, 247 million cases of malaria were reported in 2006, and it kills over 1 million people each year.2,3
Signs and symptoms
Usually beginning 10 days to 4 weeks after infection, common signs and symptoms of malaria are nonspecific and include fever, sweats, chills, headache, myalgia, and malaise. Some patients develop nausea, vomiting, and diarrhea. Malaria may also be associated with more severe signs, including splenomegaly, hepatomegaly, and tachypnea.1
Infection with the P. falciparum parasite can cause severe malaria and quickly become life threatening. Patients may experience renal failure, seizures, mental confusion, coma, and death in as little as 1 to 2 days.2 Two other malaria parasites, P. vivax and P. ovale, can stay dormant in the liver for several months up to 4 years after infection and can cause relapsing malaria.1 In this form, patients who've recovered from the first episode of illness may experience attacks, or relapses, after months or even years of being asymptomatic.4
Diagnosis and treatment
A diagnosis of malaria is based on a combination of patient history, clinical signs and symptoms, and a blood test. When taking a history, ask if the patient has traveled to a malaria-endemic area during the last 12 months. If malaria is suspected, the healthcare provider will order lab work including a blood smear to confirm the presence of malaria parasites. If the parasite is P. falciparum, lab work may reveal mild anemia, thrombocytopenia, hyperbilirubinemia, elevated aminotransferase levels, albuminuria, and urinary casts.4
In 2007, the FDA approved a rapid diagnostic test to detect antigens derived from malaria parasites. The test provides results in 2 to 15 minutes. It's approved for use in hospitals and commercial labs only, and results should be confirmed with microscopy.5
Treatment should begin within 24 hours of the onset of signs and symptoms to prevent illness progression to severe malaria, especially if the parasite is P.falciparum. Malaria can be cured if diagnosed promptly and treated correctly.
Several medications are available in the United States to treat malaria, including chloroquine, mefloquine, atovaquone-proguanil, quinine, doxycycline, and primaquine.2,6 Patients with severe malaria and those who can't take oral medications are treated via continuous I.V. infusion of quinidine gluconate.
No vaccine is available for malaria, but people planning to travel to endemic areas should take antimalarial drugs 4 to 6 weeks before travel.1 Teach travelers to take precautions to avoid mosquito bites in endemic areas. They can find out where endemic areas are by visiting www.who.int or calling their local health department.
Teach your patients the signs and symptoms of malaria and tell them to seek medical attention immediately if they occur. Explain that signs and symptoms of malaria can develop many months after exposure, even if they had antimalarial prophylaxis before travel, so they should inform healthcare providers of their travel history.
1. Centers for Disease Control and Prevention. Malaria: frequently asked questions
2. Griffith KS, Lewis LS, Mali S, Parise ME. Treatment of malaria in the United States: a systematic review. JAMA
3. World Health Organization. Fact sheet on malaria
4. Centers for Disease Control and Prevention. Malaria
5. Centers for Disease Control and Prevention. Malaria: diagnosis
6. Centers for Disease Control and Prevention. Malaria: treatment