Division of Malaria and Parasitic Diseases, National Institute of Health, Korea Center for Disease Control and Prevention, 194 Tongil-Lo, Eunpyung-Gu, Seoul, Korea.
J Travel Med. 2011 Jan-Feb;18(1):63-6. doi: 10.1111/j.1708-8305.2010.00473.x. Epub 2010 Dec 16.
There has been a great increase of Plasmodium vivax incidences in the Republic of Korea and the genetic diversity of the parasite became more complex with the rapid dissemination of newly introduced genotypes. Surveillance of imported malaria is very important, but there is no good way to determine imported vs. internal cases. In this study, we characterized imported vivax cases, analyzed the genetic sequence of three imported vivax malaria cases for the merozoite surface protein-1 (MSP-1) and circumsporozoite protein (CSP) genes, and clearly discriminated an imported vivax case that was misdiagnosed as indigenous by genetic analysis. PCR reaction for the merozoite surface protein-1 (MSP-1) and circumsporozoite protein (CSP) genes from three imported vivax cases were amplified and sequenced. The genetic variations were compared with a previously constructed database of South Korean isolates. The imported vivax cases showed various patterns on incubation period before onset. Most cases were from other parts of Asia. The MSP-1 gene sequence analysis of three imported cases showed that the imported cases had completely different sequences from any subtypes from Korean isolates. Case-1 and Case-2 exact match with an Indian isolate, and Case-3 had great similarity with isolates from countries neighboring Indonesia. 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 the usefulness of genetic survey on imported malaria cases.
韩国的间日疟原虫感染病例大幅增加，随着新引入基因型的迅速传播，寄生虫的遗传多样性变得更加复杂。对输入性疟疾的监测非常重要，但目前尚无很好的方法来确定输入性病例与本土病例。本研究对输入性间日疟病例进行了特征描述，对 3 例输入性间日疟疟疾患者的裂殖子表面蛋白-1（MSP-1）和环子孢子蛋白（CSP）基因进行了遗传序列分析，并通过基因分析清楚地区分了 1 例被误诊为本土病例的输入性间日疟病例。对 3 例输入性间日疟病例的裂殖子表面蛋白-1（MSP-1）和环子孢子蛋白（CSP）基因进行了 PCR 反应扩增和测序。将遗传变异与之前构建的韩国分离株数据库进行比较。输入性间日疟病例在发病前潜伏期有不同的表现。大多数病例来自亚洲其他地区。3 例输入性病例的 MSP-1 基因序列分析表明，输入性病例与韩国分离株的任何亚型均完全不同。病例 1 和病例 2 与印度分离株完全相同，病例 3 与印度尼西亚邻国的分离株具有高度相似性。基于重复模式的 CSP 基因分析也得出了类似的结果，即输入性病例的序列与患者的旅行国家非常匹配，与本土病例完全区分开来。AMA-1 基因分析也支持这些结果。我们利用韩国分离株的遗传数据库清楚地区分了 3 例输入性间日疟病例，并通过基因分型怀疑其来源。本研究表明，对输入性疟疾病例进行遗传调查非常有用。
