As travel to endemic regions grows, the risk of malaria in the American traveler increases as well. Worldwide, an estimated 250 million cases and 1 million deaths were reported in 2008 alone. The United States has approximately 1,500 cases and 15 deaths every year. A few “hot spots” account for most cases. Travel to Nigeria, India, Ghana, Uganda, Afghanistan, and Honduras accounts for 60% of cases. Fifty percent of cases present to the urban emergency departments of New York, California, Texas, Georgia, and Illinois.²

Although just 20% of travelers take appropriate prophylaxis, it is important to inquire about the specific medication taken. Not all prophylaxis is created equal. Dormant liver forms of P. vivax and P. ovale may lead to relapse months to years after travel if mefloquine, doxycycline, or atovaquone-proguanil (Malarone) is not used. The area of travel should also be investigated for chloroquine-resistance via the Centers for Disease Control and Prevention’s Malaria Web site.

Lastly, adherence to the regimen for prophylaxis should be assessed as intermittent dosing can mask subclinical parasitemia.

The symptoms of malaria mimic a viral syndrome or gastroenteritis. More than 75% of cases will present with fever, chills/rigors, and headache. In 50% of cases, symptoms will include fatigue, anorexia, arthralgia, or nausea/emesis.³ Occasionally, patients will report a periodic fever with spikes occurring every 48 to 72 hours—a classic but unreliable sign of malaria.

Physical exam findings that are consistent with uncomplicated malaria include hepatosplenomegaly (indicating hemolysis and sequestration), mild abdominal tenderness, and evidence of mild dehydration.

Severe malaria (see sidebar) indicates heightened parasitemia and is a true medical emergency. The presence of coma indicates cerebral malaria, which is uniformly and rapidly fatal if untreated. Special attention should be given to pregnant women with malaria, as they are relatively immunocompromised and decompensate quickly.⁵

ED Work-Up and Management

The clinician evaluating fever in the recent traveler must remember the seven deadly infections that can kill within hours of presentation if not treated urgently and appropriately. These are summarized by the mnemonic HERE I AM: Hantavirus, Ebola, Rabies, Enteritis, Influenza, Arboviruses (e.g., Dengue and West Nile), and Malaria.