Update: Malaria, U.S. Armed Forces, 2021.

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 2021, a total of 20 service members were diagnosed with or reported to have malaria. This was the lowest number of annual cases during the 10-year surveillance period (i.e., January 2012-December 2021) and represents a 28.6% decrease from the 28 cases identified in 2020. The relatively low numbers of cases during 2012-2021 mainly reflect decreases in cases acquired in Afghanistan, a reduction largely due to the progressive withdrawal of U.S. forces from that country. The percentage of 2021 cases of malaria caused by Plasmodium falciparum (55.0%; n=11) was the highest of any year of the surveillance period; however, the number of cases was the third lowest observed during the surveillance period. The number of malaria cases caused by Plasmodium vivax in 2021 (n=1) was the lowest observed during the surveillance period. The remaining 8 malaria cases were labeled as associated with other/unspecified types of malaria (40.0%). Malaria was diagnosed at or reported from 15 different medical facilities in the U.S.; only 2 were reported outside of the U.S., 1 each in Germany and Africa. Providers of medical care to military members should be knowledgeable of and vigilant for clinical manifestations of malaria outside of endemic areas.