Abstract: Objective To explore circumsporozoite protein (CSP) genotype structure of Plasmodium vivax in southern China and evaluate its epidemiological significance. Methods Filter paper blood samples were collected from 346 vivax malaria patients in 5 provinces （Autonomous Region）including Hainan, Yunnan, Guangxi, Guangdong and Guizhou for identifying CSP genotypes, by using the method of single-tube nested/multiplex PCR. The findings combined with relevant data were statistically analyzed. Results In Guangdong, Guangxi and Guizhou Provinces（Autonomous Region）, the temperate zone family strains accounted for more than 90%, with only a few tropical zone family strains and no PV-type II each strain. In Yunnan Province, temperate strains and tropical strains accounted for 71.4% and 28.6% respectively, with occasional PV-type II strain. In Hainan Province, strains of temperate zone, tropical zone and PV-type II accounted for about one-third. Conclusions The temperate zone family strains were the predominant ones in the Provinces（Au-tonomous Region） of Guangdong, Guangxi and Guizhou where malaria control was carried out effectively; while in Hainan and Yunnan Provinces the difficulties in malaria control may probably be related to the complex structure of P. vivax population and multiple infections of different genotypes. The findings indicate that the complexity of the P. vivax genotype structure might be an indicative epidemiological feature for malaria control and surveillance.

Key words: Plasmodium vivax, Circumsporozoite protein, Genotype, Control effect