Allele genetypes and homology analysis of MSP-1 and CSP gene of Plasmodium vivax in Shandong Province

Abstract

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. 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. 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. 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.