Outbreak of vivax malaria in areas adjacent to the demilitarized zone, South Korea, 1998.

Malaria had been eradicated in the Republic of Korea (South Korea) by the late 1970s. In 1993, a soldier was infected with Plasmodium vivax malaria in the Demilitarized Zone (DMZ; the border area between North and South Korea), and since then, the number of cases has been steadily increasing year after year. In 1998, 3,932 vivax malaria cases were microscopically confirmed, affecting 2,784 (70.8%) soldiers (including discharged soldiers) and 1,148 (29.2%) civilians. These cases occurred throughout the year, peaking in July (30.1%) and August (30.5%). Most of the patients were infected in areas in or near the DMZ. Taking into consideration entomologic, socioecologic, and epidemiologic factors, it is postulated that there has been an epidemic of malaria in North Korea since 1993, with the number of cases increasing yearly; the continuous infiltration across the DMZ from North Korea of infected female mosquitoes of the vector species Anopheles sinensis resulted in an outbreak of vivax malaria in the DMZ of South Korea.