Rescind: Malaria in U.S. Traveler to Costa Rica

CDC is rescinding its malaria notice posted on May 10, 2018 regarding a case of P. falciparum malaria in a U.S. traveler who returned from Costa Rica. 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 (RDT) at the hospital was positive, and testing at a state health department laboratory with polymerase chain reaction (PCR) was positive for P. falciparum malaria. However, further testing at CDC’s laboratory with two methods of PCR, antigen detection, and serology were all negative. The conclusion is the previous RDT and PCR were false positives, and that there is no evidence of malaria in this patient.

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.

While no malaria prophylaxis is recommended, travelers should continue to take measures to avoid mosquito bites, as other diseases can be spread by mosquitoes. 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.

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 Travelers’ Health website.

Page last reviewed: May 22, 2018