Usefulness of Circumsporozoite Protein Genotype-Specific PCR (Polymerase Chain Reaction)-Hybridization Assay for Diagnosis of Vivax Malaria

Lee, Chan Ju; Park, Ki Ho; Park, Dae Won; Lee, Jong Sup; Kim, Kyoung Oh; Sohn, Jang Wook; Yong, Mi Sun; Lim, Chae Seung; Park, Seung Chul; Kim, Min Ja

Abstract

BACKGROUND: Molecularornucleicacid-based method has been developed for diagnosis as well as epidemiological studies of malaria infection recent years. We developed and evaluated a polymerase chain reaction (PCR)-hybridization assay for its usefulness in diagnosis and genotyping of vivax malaria resurged in South Korea. METHODS: Blood samples were collected from 30 patients diagnosed as vivax malaria and 48 patients with other diseases. The circumsporozoite protein (CSP) gene fragment of Plasmodium vivax was amplified by PCR and hybridized with genotype (VK210 or VK247)-specific oligonucleotide probes. The performance of the assay was evaluated and compared with that by a commercially available immunochromatographic test (ICT; AMRAD, Australia). RESULTS: Twenty-five out of thirty P. vivax-positive blood samples were positive for the PCR-hybridization assay. All products amplified were hybridized only with the VK210-specific probe and showed size polymorphism with approximately 900~ and 865 bp, suggesting of genetic variations of CSP gene. Based on the results of Giemsa-stained blood smear, comparative analysis of test performance demonstrated that sensitivities of the PCR-hybridization assay and ICT were 83.3% and 73.3%, respectively and no false positive results were found. The ktest ratio of two tests yielded results of 0.91 with excellent correlation. CONCLUSOIN: The study suggested that vivax malaria resurged in South Korea has the VK210 genotype of CSP with presence of genetic variants, and that the PCR-hybridization assay is useful for diagnosis as well as genotyping of vivax malaria.