Review Question - QID 104927

This patient is traveling to the Amazon basin, which contains chloroquine-resistant malaria. Proper agents for prophylaxis include mefloquine, atovaquone-proguanil, and doxycycline.

Regions of chloroquine-resistant malaria include Sub-Saharan Africa, the Amazon basin, and south and southeast Asia. The clinical presentation of malaria includes cyclic fevers at 48-72 hour intervals (except P. falciparum, which has irregular fever spikes of 36-48 hours), shaking chills, and soaking sweats. Other signs include anemia (hemolytic), splenomegaly (typically after >4 days of symptoms), and agitation. Of note, patients are often asymptomatic between attacks. Complications include cerebral malaria and severe hemolytic anemia.

Re and Gluckman discuss the epidemiology of malaria, reporting that the growing popularity of tropical travel has increased the risk for acquiring malaria. They report an incidence in 1998 of more than 270 million cases of malaria worldwide, with more than 1 million deaths. In the United States, approximately 1,500 cases of malaria are reported annually to the CDC. Physicians must pay close attention to which countries their patients are visiting within malaria-endemic areas and drug-resistant zones.

Prince et al. analyzed the incidence of chloroquine resistance in a meta-analysis. They determined rates of chloroquine resistance according to P. vivax malaria recurrence rates by day 28 whole-blood chloroquine concentrations at the time of recurrence. Resistance was present in 58 (53%) of 113 study sites, spread across most countries that are endemic for P. vivax.

Illustration A shows a world map of chloroquine resistance; the green-shaded areas exhibit chloroquine resistant malaria, while the yellow-colored countries have chloroquine sensitivity.

Incorrect Answers:
Answers 2-5: These agents are all used for chloroquine-resistant malaria prophylaxis. Quinine is effective but not routinely used because of side-effects.