Unstable vivax malaria in Korea

Abstract

Korean vivax malaria had been prevalent for longtime throughout the country with low endemicity. As a result of the Korean war (1950-1953), malaria became epidemic. In 1959-1969 when the National Malaria Eradication Service (NMES) was implemented, malaria rates declined, with low endemicity in the south-west and south plain areas and high endemic foci in north Kyongsangbuk-do (province) and north and east Kyonggi-do. NMES activities greatly contributed in accelerating the control and later eradication of malaria. The Republic of Korea (South Korea) was designated malaria free in 1979. However, malaria re-emerged in 1993 and an outbreak occurred in north Kyonggi-do and north-west Kangwon-do (in and/or near the Demilitarized Zone, DMZ), bordering North Korea. It has been postulated that most of the malaria cases resulted from bites of sporozoite-infected females of An. sinensis dispersed from North Korea across the DMZ. Judging from epidemiological and socio-ecological factors, vivax malaria would not be possible to be endemic in South Korea. Historical data show that vivax malaria in Korea is a typical unstable malaria. Epidemics may occur when environmental, socio-economical, and/or political factors change in favor to malaria transmission, and when such factors change to normal conditions malaria rates become low and may disappear. Passive case detection is a most feasible and recommendable control measure against the unstable vivax malaria in Korea in cost-effect point of view.

Late season commercial mosquito trap and host seeking activity evaluation against mosquitoes in a malarious area of the Republic of Korea

“…Starting in 1993, autochthonous malaria (Plasmodium vivax) reemerged along the DMZ, and quickly spread through the civilian and military communities to become a primary health threat in Kangwon and Kyonggi Provinces bordering the DMZ (Kho et al, 1999;Ree, 2000). Prior to 1993, few authorities considered the reemergence of malaria in the ROK a reasonable possibility.…”

Molecular Genetic Characterization of the Merozoite Surface Protein 1 Gene of Plasmodium vivax from Reemerging Korean Isolates

“…Few data examining the recent intensity of malaria transmission in Korea are available. It is believed that the opportunity for malaria transmission by mosquitoes might be strictly limited, since transmission takes place during a limited season, from May to October, and the transmission ability of the vector mosquito may be extremely low (22). Also, the frequency of human-vector (Anopheles sinensis) contact is very low, because A. sinensis is highly zoophilic (23), there is widespread application of personal protection against mosquito bites (17), and A. sinensis has very low to moderate longevity in Korea (16).…”

Resurgence of Plasmodium vivax Malaria in the Republic of Korea during 2006–2007

“…2,3 Through improved national economic conditions and continuous malaria control programs, P. vivax malaria cases in the Republic of Korea (ROK) tapered off in the 1960s and 1970s, and, finally, ROK was declared malariafree in 1979. 4,5 However, P. vivax malaria re-emerged in ROK in 1993, and its annual incidence rapidly increased up to more than 4,000 cases in 2000, 6 fell to 864 cases in 2004, and rose again in 2005. 7,8 During the early period of re-emergence, P. vivax malaria in ROK may have been mostly caused by infected Anopheline mosquitoes originating from the Democratic People's Republic of Korea (DPRK; North Korea) near the Demilitarized Zone (DMZ), as evidenced by epidemiologic and demographic data.…”