Objective: To analyze the genotypes and homology of MSP-1 and CSP gene of Plasmodium vivax in Shandong Province, so as to provide the evidence for case traceability.
Methods: A total of 12 blood samples were collected from P. vivax-infected cases in Shandong Province in 2011. Parasite genomic DNA was extracted. Primers were designed according to MSP-1 and CSP gene sequences of P. vivax. Then Nested PCR, enzyme digestion, sequencing and sequence alignment, and homologous analysis were performed.
Results: The MSP-1 gene of all the 12 samples from P. vivax-infected cases were detected with a 470 bp PCR amplification band, and 350 bp and 120 bp enzyme digestion fragments, which were identified as type Sal-1. An analysis of phylogenetic tree of MSP-1 gene showed that the sequences of 9 indigenous case samples in Shandong Province were located in the same branch, one case sample infected from India was located in the same branch with India strains. All the 12 P. vivax-infected samples covered GDRA (D/A) GQPA sequences in CSP gene, which were identified as type PV-Ⅰ. Of the CSP gene among 12 P. vivax-infected samples, 10 samples of indigenous case in Shandong Province and one sample of the case infected in Guangdong Province were detected with both 560-840 bp and 150-230 bp PCR amplification bands, which were identified as temperate zone family strain of type PV-Ⅰ. However, one sample from the case infected in India was detected only with a 560-840 bp band, which was identified as tropical zone family strain of PV-Ⅰ. An analysis of phylogenetic tree of CSP gene showed that the sequences of 10 samples from the indigenous cases in Shandong Province and one sample from the case infected in Guangdong Province were located in the same branch, one sample from the case infected in India was located in the same branch with India and Indonesia strains.
Conclusions: Of all the indigenous isolates in Shandong Province, MSP-1 gene is genotyped type Sal-1, CSP gene is genotyped temperate zone family strain of type PV-Ⅰ, with a high homology found among the indigenous isolates.
［摘要］ 目的 分析山东省间日疟原虫MSP-1和CSP基因类型及其同源性, 为病例溯源提供科学依据。 方法 采集 2011年山东省报告的12例间日疟患者血样, 提取疟原虫基因组DNA; 分别根据间日疟原虫MSP-1和CSP基因序列设计 引物, 进行巢式PCR 扩增、酶切、测序、序列比对及同源性分析。 结果 12份间日疟患者血样MSP-1基因全部出现470 bp扩增条带以及350、120 bp酶切片段, 均为Sal-1型; MSP-1进化树分析显示, 9份省内感染者样品序列同属一个分枝, 1 份印度感染者样品序列与印度分离株位于同一分枝。12份间日疟患者样品CSP基因均包含GDRA (D/A) GQPA序列, 为 PV-Ⅰ型, 其中10份省内感染者和1份广东感染者样品CSP基因出现560～840 bp和150～230 bp两种扩增条带, 为PV-Ⅰ型温带族, 1份在印度感染者样品CSP基因仅出现560～840 bp条带, 为PV-Ⅰ型热带族。CSP进化树表明, 10份省内 感染者及1份广东感染者样品序列同属一个分枝, 1份在印度感染者样品序列与印度和印度尼西亚分离株位于同一分 枝。 结论 山东省本地感染间日疟原虫MSP-1基因型均为Sal-1型, CSP基因型均为PV-Ⅰ型温带族, 本地虫株具有较强 的基因同源性。.
Keywords: CSP gene; Genotyping; Homology; MSP-1 gene; Plasmodium vivax; Shandong Province.