Decreasing incidence of Plasmodium vivax in the Republic of Korea during 2010–2012

Abstract

BackgroundAfter the re-emergence of Plasmodium vivax in 1993, a total of 31,254 cases of vivax malaria were reported between 1993–2012 in the Republic of Korea (ROK). The purpose of this study was to review Korea Centers for Disease Control and Prevention records to investigate the transmission of malaria from 2010–2012.MethodsReporting of microscopy-diagnosed cases of malaria is mandatory in the ROK. In this study, all available records of malaria cases and malaria vectors collected from 2010 – 2012 in Cheorwon County, Gangwon Province and Ganghwa County, Incheon Metropolitan City, were reviewed.ResultsAlthough the number of cases of malaria peaked a third time in 2010 (1,772 cases) since the re-emergence of P. vivax, the incidence decreased two-fold to 838 in 2011 and three-fold to 555 in 2012. The number of cases decreased 52.7% in 2011 compared with that in 2010 and 33.8% in 2012 compared with that in 2011. However, the number of cases increased in Incheon Metropolitan City (15.3%) and Gyeongnam Province (23.1%) in 2012 compared with 2011. Of the 3,165 cases of vivax malaria in 2010–2012, 798 (25.2%) were in ROK military personnel, 519 (16.4%) in veterans, and 1,848 (58.4%) in civilians. In total, there were 2,666 male patients and 499 female patients, and the ratio of female to male patients increased from 1:7.9 in 2011 to 1:4.1 in 2012.ConclusionsA rapid decrease in the incidence of malaria was observed in most areas from 2010 to 2012, but the incidence increased again in the western part of the demilitarized zone. Therefore, more intensive surveillance is needed throughout high risk areas to identify factors responsible for increase/decrease in the incidence of malaria in the ROK.

Clinical Characteristics of Vivax Malaria Outside Northern Gyeonggi Province Korea

“…Most of our study patients were discharged soldiers, and the majority of these developed malaria within the 12 months after military discharge (93.6%, 73/78). In addition, most cases (97.1%, 101/104) occurred between May and October, peaking in July and August, similar to peaks reported by the majority of previous studies [1, 6]. The mean patient age was lower than in the endemic area reported by Kwak et al [1], and almost all of our study patients were male.…”

Sequence conservation of Plasmodium vivax glutamate dehydrogenase among Korean isolates and its application in seroepidemiology

“…After that, reported cases of malaria declined again for several years, owing to nationwide efforts to reduce the incidence of this disease. However, malaria has not been eradicated from the Korean peninsula because many travellers and workers come from areas where malaria is prevalent, including North Korea [29]. For these reasons, serological diagnostic tools are needed to support both traditional microscopic diagnosis and antibody testing on a population level to gain an estimate of exposure to malaria in Korea.…”

Changing Vivax Malaria Transmission Features in the Republic of Korea during 2013-2014

“…In addition, the annual mean precipitation in 2014 (1,173.5 mm) was slightly higher than that in 2013 (1,162.9 mm) (Table 2) [27]. Taking these observations together, it can be inferred that the increased number of patients in 2014 was closely related to elevated temperature, precipitation, and vector density.…”

“…The mean temperature during the summer season of 2014 was lower than that of 2013, whereas the mean temperature in the spring and autumn season of 2014 was higher than that of 2013 (Table 2) [27].…”