Malaria in U.S. Traveler to Costa Rica

On May 4, 2018, a case of P. falciparum malaria in a U.S. traveler who returned from Costa Rica was reported to CDC. The 54-year-old man was traveling in the Osa Peninsula in Puntarenas Province in Costa Rica April 7–20, 2018, for ecotourism. Seven days after returning, he developed fever, body aches, and gastrointestinal symptoms, and was admitted to the hospital. Thick and thin blood smears for malaria were negative, but a malaria rapid diagnostic test was positive. Further testing with polymerase chain reaction confirmed P. falciparum malaria. This patient was treated with atovaquone-proguanil and fully recovered. Costa Rica had no local transmission of malaria from 2013 through most of 2016. Then, at the end of 2016, 4 cases of locally transmitted P. vivax were reported, and again in 2017 9 cases of P. vivax were reported, all in the northern part of the country. The Osa Peninsula is at the southern part of Costa Rica bordering a part of Panama that has had rare P. falciparum cases, but none in the previous two years. Because of the very limited transmission, travelers to this area had been previously advised to practice only mosquito avoidance measures to prevent malaria.

CDC recommends that travelers to the Osa Peninsula in Costa Rica take medications to prevent malaria. Effective antimalarial options include atovaquone-proguanil, chloroquine, doxycycline, and mefloquine.

As malaria and other diseases are spread by mosquito bites, CDC recommends that travelers use mosquito avoidance measures. These measures include using insect repellent when outdoors, wearing protective clothing, staying in an air-conditioned or well-screened area, and sleeping under an insecticide-treated bed net.

CDC will continue to monitor the malaria situation in Costa Rica and will update these recommendations as needed.

See the CDC malaria website for additional health information about malaria including prevention of mosquito bites and drugs for malaria prevention. For general health information for travelers to all areas of the world, see the CDC Traveler’s Health website.

Page last reviewed: May 10, 2018