Resurgence of Plasmodium vivax malaria in the Republic of Korea during 2006-2007.

Plasmodium vivax malaria, which re-emerged in the Republic of Korea (ROK) in 1993, had decreased since 2001. However, case numbers began to increase again in 2005. The number of cases rose 54.0% in 2006, but the rate of increase slowed down in 2007. Among the total of 4,206 cases of P. vivax malaria during 2006-2007, 756 cases (18.0%) were ROK military personnel, 891 cases (21.2%) were veterans, and 2,559 cases (60.8%) were civilians. The rapid increase during this period was mostly contributed by the western part of the malaria-risk areas that is under the influence of adjacent North Korea. Local transmission cases in ROK have also increased gradually and the transmission period seemingly became longer. Chemoprophylaxis in the military should be re-assessed in view of chloroquine-resistance. Continuous surveillance and monitoring are warranted to prevent further expansion of P. vivax malaria caused by climate change in ROK.