CSP gene analysis based on the repeat patterns showed similar results that the sequences from the imported cases well matched with the patient’s traveled countries and completely discriminated with indigenous cases. AMA-1 gene analysis also supported these results. We were able to clearly distinguish three imported vivax cases from indigenous by using a genetic database of Korean isolates and were able to suspect its origin by genotyping. This study demonstrated Cyclopamine order the usefulness of genetic survey on imported malaria cases. Plasmodium
vivax is the most widespread of four Plasmodium species that infect humans. Recently, P vivax resistance to antimalarial drugs has been increasing.1 Migration R428 and tourism to malaria-endemic regions increase the threat of malaria importation.2 Since reemergence in 1993, vivax malaria is endemic in Korea, with seasonal prevalence. Between 1994 and 2008, 621 cases of imported malaria were reported in South Korea. Among imported cases from 2002 to 2008, 36.8%
were P vivax.3 An intriguing vivax case (case 2) was reported in July 2008 and initially misdiagnosed as autochthonous because the patient lived in the malaria-endemic area and had symptoms during malaria season in Korea (Table 1). The epidemiological survey revealed that the patient had traveled in Southeast Asia (mainly India; Table 1), and a 6-month incubation period before onset occurred similarly to Korean malaria. Previously, we demonstrated that the genetic variation of P vivax malaria in Korea has increased in complexity, compared to earlier strains, due to rapid dissemination of newly introduced
malaria.4 Thus, it is crucial to survey and control the import of malaria to prevent the spread of new subtypes and minimize genetic diversity in malaria-endemic and malaria-free countries. The ability to discriminate between imported and autochthonous malaria cases has been limited. In this study, however, we were able to discriminate between these cases using genotyping based on the Y-27632 2HCl genetic database we systematically analyzed previously.4 We focused on P vivax MSP-1 (PvMSP-1) and CSP (PvCSP) genes, which are highly polymorphic5 and also well analyzed in Korean vivax malaria,4 to (1) assess the genetic identity between imported and autochthonous isolates and (2) confirm the geographical origin of the parasite. Interspecies conserved block 5 (ICB5) and ICB6 of the MSP-1 gene are valuable geographical markers with high polymorphic patterns, dependent on three major types (Sal-I, Belem, and Recombinant) and their subtypes.6PvCSP, which contains repeat sequence motifs, is also a useful marker for identifying geographical isolates.7 Two main P vivax CSP gene types occur, VK210 and VK247. The VK210 type displays variations according to the number of peptide repeat motifs: GDRA(A/D)GQ(P/A)A, GNGAGGQ(A/P)A, GGNA, and ANKKAEDA.