Update: Malaria, U.S. Armed Forces, 2017.

Malaria infection remains an important health threat to U.S. service members who are located in endemic areas because of long-term duty assignments, participation in shorter-term contingency operations, or personal travel. In 2017, a total of 32 service members were diagnosed with or reported to have malaria, which is the lowest number of cases in any given year during the 10-year surveillance period. The relatively low numbers of cases during 2012-2017 mainly reflect decreases in cases acquired in Afghanistan, a reduction due largely to the progressive withdrawal of U.S. forces from that country. The percentage of cases of malaria caused by unspecified malaria species (53.1%; n=17) in 2017 was the highest during any given year of the surveillance period. The percentages of cases caused by Plasmodium vivax (15.6%; n=5), P. falciparum (25.0%; n=8), and by P. malariae (6.3%, n=2) remained similar to those of the preceding 4 years, although the numbers of cases decreased. Malaria was diagnosed at or reported from 19 different medical facilities in the U.S., Afghanistan, Qatar, Germany, Djibouti, Japan, and Korea. Providers of medical care to military members should be knowledgeable of, and vigilant for, clinical manifestations of malaria outside of endemic areas.