Chemoprophylaxis and the epidemiological characteristics of re-emergent P. vivax malaria in the Republic of Korea

Abstract

Objective In the Republic of Korea (ROK), soldiers stationed where there is a risk of contracting malaria have received antimalarial chemoprophylaxis since 1997. However, chemoprophylaxis may facilitate the development of drug resistance, and late primary attacks in individuals who have received chemoprophylaxis are becoming more frequent. We investigated the association between chemoprophylaxis and the epidemiological characteristics and effectiveness of treatment for re-emergent Plasmodium vivax malaria, using a nationwide malaria database. Methods Among soldiers at risk of malaria between 1999 and 2001, we reviewed all P. vivax malaria cases (1158) that occurred before 31 December 2003. Early and late primary attacks were defined as cases occurring < 2 or > 2 months after the last day of exposure to risk of malaria, respectively. Findings Of these cases, 634 (72.0%) had received chemoprophylaxis, and 324 (28.0%) had not. Cases occurred mostly in summer, with a peak in July-August. Stratification by chemoprophylaxis history revealed different times to onset. Early primary attacks were more prevalent in the group not receiving chemoprophylaxis, while in the group receiving chemoprophylaxis most cases were late primary attacks. Of the latter, 312 out of 461 (67.7%) did not take primaquine regularly. After treatment of the first attack, 14 (1.2%) of 1158 were re-treated; all re-treated cases were cured using the same doses and regimen used for the first treatment. Conclusion In ROK, the increase in late primary episodes of re-emergent P. vivax malaria is associated with the use of antimalarial chemoprophylaxis.Bulletin of the World Health Organization 2006;84:827-834.Voir page 833 le résumé en français. En la página 833 figura un resumen en español. IntroductionPlasmodium vivax, the causative agent of vivax malaria, has been endemic in the Republic of Korea (ROK) for cent t turies. The number of cases of endemic malaria began to decline in the 1960s, partly due to increased socioeconomic development, increased use of agricult t tural pesticides, and the efforts of the National Malaria Eradication Service. These factors contributed to the eradicat t tion of malaria in the ROK, resulting in the declaration by WHO in 1979 that the country was malariatfree. 1 In 1993, one case of malaria attributed to autot chthonous transmission was detected near the demilitarized zone (DMZ) that separates ROK (south) from the Democratic People's Republic of Korea (north).2 Since 1993, the number of malaria cases has increased exponentially, particularly among soldiers based near the DMZ. [1][2][3][4][5] Chemoprophylaxis and the epidemiological characteristics of re-emergent P. vivax malaria in the Republic of Korea In ROK, healthy males aged over 18 years serve 26 months of mandat t tory military duty; most are stationed throughout their service near the DMZ, where the risk of malaria is highest. After finishing their military duty, the soldiers return from these risk areas to areas with little or no malaria. To reduce the occurren...

Antimalarial Drug Susceptibility of Plasmodium vivax in the Republic of Korea

“…26 Chloroquine and primaquine have been used for the radical cure of patients with P. vivax malaria that originated in the Republic of Korea. 5,27,28…”