Malaria: Prevent, Diagnose, and Treat

Kathrine K. Tan, MD, MPH


April 21, 2014

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Hello. I am Dr. Kathrine Tan, a Medical Officer in the Malaria Branch of CDC. I am pleased to speak with you as part of the CDC Expert Commentary series on Medscape.

Malaria is increasingly reported in the United States. There were 1925 cases reported in 2011 -- the largest number of reported cases since 1971. I will discuss the prevention, diagnosis, and treatment of malaria.

Prevention. Malaria is a disease that is potentially fatal but preventable. Malaria was eliminated in the United States in the 1950s; however, cases of malaria continue to be reported in the United States, mostly in travelers who went to countries where malaria is transmitted and return with a malaria infection. Most of these cases could have been prevented.

The first step in prevention is to learn whether a patient will soon be traveling to an area with malaria. In particular, ask first- and second-generation immigrants from malaria-endemic countries about future travel plans to their country of origin, because many of the imported malaria cases are in those who travel to visit friends and relatives. If patients are seeking travel advice, ask for a detailed itinerary, because malaria endemicity can vary between different regions within a country. If the traveler is going to a malaria-endemic area, the most appropriate malaria prevention measures can be determined -- either drugs and mosquito avoidance, or mosquito avoidance only.

If drug prophylaxis is recommended, many antimalarial drugs are available, and the selection of the drug depends on the area of travel, the presence of antimalarial resistance, the patient's medical conditions and current medications, and the potential for side effects. CDC maintains a country-by-country listing of recommended malaria prevention measures online at or in CDC's The Yellow Book.

It is important to counsel all patients going to an area with malaria transmission about mosquito avoidance measures, such as wearing an effective mosquito repellent on exposed parts of the skin and sleeping under an insecticide-treated bednet. Patients should also be counseled to seek medical evaluation immediately if they develop fever during or after travel.

Diagnosis. Malaria symptoms are nonspecific -- fever, headache, and malaise -- and can occur at intervals. Ask about recent travel in any patient who presents with fever. Any patient with fever and a history of travel to a malaria-endemic area should be tested right away for malaria. Malaria is diagnosed with microscopy: specifically, a thick and thin blood smear. The results should be made available on the same day, because malaria is considered an emergency and can quickly progress if not diagnosed and treated promptly.

A rapid diagnostic test for malaria can be used to diagnose malaria to facilitate timely treatment; however, it should be followed immediately by malaria microscopy, because only a blood smear can give information on the malaria species and level of parasitemia, which are key for malaria management. It is vital that clinicians have access to appropriate diagnostic tests on site, because empiric treatment for malaria is not recommended. CDC can also confirm the parasite species and evaluate the parasite for drug resistance.

Treatment. To choose an appropriate antimalarial for treatment, consider disease severity, malaria species, the likelihood of drug resistance based on where the infection was acquired, the age of the patient, and pregnancy status. Severe malaria is characterized by having at least 1 of the following complications: high parasitemia (> 5%), altered mental status, acute respiratory distress syndrome, renal failure, severe anemia, or jaundice.

To treat severe malaria, intravenous (IV) antimalarials are used. Quinidine is the only IV antimalarial approved for use in the United States, but IV artesunate is also available through CDC. Uncomplicated malaria can be treated with oral antimalarials. Consultation with a physician trained in infectious disease, travel, or tropical medicine is highly recommended.

CDC's Malaria Branch staff is available 24/7 to provide consultations on malaria and to assist with inquiries about IV artesunate through the Malaria Hotline. For more information about malaria, and the Malaria Hotline number, visit Thank you for watching this CDC Expert Video Commentary on Medscape.

Web Resources

CDC: Malaria

CDC: Travelers' Health

Kathrine K. Tan, MD, MPH, is a medical epidemiologist in the Malaria Branch in the Center for Global Health of the Centers for Disease Control and Prevention (CDC), where she develops the guidelines for malaria prophylaxis for travelers, provides clinical consultations for cases of malaria, leads projects related to malaria prevention and management, has provided technical support for the President's Malaria Initiative, and conducts various operational research projects in Zambia. Previous to this, she was an Epidemic Intelligence Service Officer at CDC with the Division of Tuberculosis Elimination. She is board-certified in both family medicine and preventive medicine and has a certificate in travel medicine from the International Society of Travel Medicine. She graduated from the University of California at Davis School of Medicine; completed a family medicine residency, also at UC Davis; and completed a preventive medicine residency at CDC.