我国间日疟原虫基因型种群结构及其地理分布

目的　用分子技术调查中国间日疟原虫种群结构与地理分布。　方法　用滤纸血滴法采集我国 10个省 (自治区 )间日疟现症病人血样 ,用套式 、半套式 等位特异PCR基因分型法鉴定其型、族归属及其CSP基因型 ,并作流行病学统计分析。　结果　在 384个间日疟原虫分离株中 ,检出温带族 2 5 8株 ,分为 14个不同的(等位变异 )基因型 ,遍布全国各省 ,其中主带≤ 731bp的基因型仅见于南方 5省 ;热带族 79株 ,分为 5个不同基因型 ,分布于北纬 2 5°以南的 5个省 (自治区 ) ;PV 2型 16株 ,包括 2个基因型 ;另 33个分离株为不同型(族 )或不同基因型虫株的重复 (混合 )感染。　结论　目前我国北纬 2 5°以北各省是单一温带族间日疟原虫分布区 ,北纬 2 5°以南地区是温带族与热带族间日疟原虫重叠分布区 ,其中海南和云南两省局部地区同时尚存在PV 2型 ;温带族内存在地理分布明显不同的 2个基因类群。

Investigation on Genotype Constitution of Different Plasmodium vivax Isolates and its Geographical Distribution in China

OBJECTIVE: To investigate the population constitution and geographical distribution of Plasmodium vivax in China using molecular technique. METHODS: Blood-spot filter paper samples with related epidemiological data were collected from vivax malaria patients living in malarious area of 10 provinces (autonomous region) in China. Semi-nested- or nested-allelic-specific PCR genotyping method was used to identify CSP genotypes, families and types of Plasmodium vivax of each isolate from these patients. RESULTS: Of 384 field isolates of Plasmodium vivax, 258 temperate zone family strains were identified, including 14 allelic variant genotypes spreading among 10 sampling provinces; allelic variants sized less than 731 bp were only seen in 5 provinces in southern China; 79 tropical zone family strains including 5 genotypes were also distributed in 5 provinces of southern China south to 25 degrees N. lat; and 14 PV Type-2 strains including 2 genotypes were found in some areas of Hainan and Yunnan Provinces. In addition, 33 isolates from genotype-mixed infections were revealed. CONCLUSION: At present, area north to 25 degrees N. lat. of the country is the sole area prevalent for Plasmodium vivax family strains of temperate zone; there is overlapping distribution of P. v. of temperate zone family and tropical zone family of this parasite in the southern China south to 25 degrees N. lat; where the most complex isolate constitution is in Yunnan and Hainan Provinces, and PV Type-2 strains have been found in some areas of the two provinces. Besides, there were 2 groups of genotype with distinct geographic distribution feature within the temperate zone family.