Epidemiological studies of vivax malaria high ristk areas using circumsporozoite protein

초록

Vivax malaria seems like to continue affect on public health until the eradication even it shown that the number of patients reduced with fluctuation after reemerged in Korea at 1993. Therefore we tried to figure out whether circumsporozoite protein (CSP), the representative antigen of Plasmodium vivax, could estimate the current prevalence in this study. We collected blood samples from inhabitants of high risk areas in Gangwha-gun and Cheorwon-gun, 1825 and 1959 blood samples in 2010 and 2011, respectively. Antibody titers of inhabitants in high risk areas were measured by enzyme-linked immunosorbent assay (ELISA) using CSP antigen purified from bacteria. Annual parasite index (API) in Gangwha-gun was reduced from 4.28 in 2010 to 2.23 in 2011, and in Cheorwon-gun was from 1.88 in 2010 to 1.15 in 2011. Positive rate of CSP in these areas was also reduced from 331 (18.14%) in 2010 to 301 (15.26%) in 2011. It showed significant relationship between positive rate of CSP and API of 2010 (P = 0.0009) and 2011 (P = 0.0002). Intensity of immune responses of inhabitants from Cheorwon-gun was reduced in mean optical density from 0.9186 ± 0.0472 in 2010 to 0.7035 ± 0.0457in 2011, but it was not changed significantly in Gangwha-gun from 0.7649 ± 0.0192 in 2010 0.8237 ± 0.1970 in 2011. Together with these results, we could predict the malaria prevalence would keep continue in Gangwha-gun and reduce in Cheorwon-gun near future. In fact, malaria patients of Gangwha-gun in 2012 showed similar to previous year as 92.7% (55  51), interestingly malaria patients of Cheorwon-gun in 2012 from 64 to 6 (9.4%). It showed dramatic reduction of patients in Cheorwon. Even it should be keep continue similar researches, positive rates of CSP itself in prevalent areas could reflect the malaria prevalence in current and following years.