丙型肝炎病毒家庭内传播的4年随访和分子流行病学调查

Four-year follow-up and molecular epidemiologic investigationof intrafamilial transmission of HCV infection

为研究ＨＣＶ感染的家庭内聚集现象，对某自然村ＨＣＶ感染状况进行了４年随访和分子流行病学调查。应用逆转录巢式多聚酶链反应（ＲＴ－ＮｅｓｔｅｄＰＣＲ）、ＯｋａｍｏｔｏＨＣＶ基因分型法及ＳＳＣＰ法分析ＨＣＶ核心区基因变异。结果：抗ＨＣＶ和／或ＨＣＶＲＮＡ阳性率由４年前的２１．３１％增加至４３．１８％。家庭成员有≥２人抗ＨＣＶ和ＨＣＶＲＮＡ阳性的５２户，也较４年前增加３．４６倍。经用Ｏｋａｍｏｔｏ法基因分型［１］，该村ＨＣＶ基因型主要为１ｂ／Ⅱ型，占９０．６７％，其余为２ａ／Ⅲ型，占１．３３％，两者混合感染占２．００％。进一步用ＤＮＡ单链构象多态性分析（ＳＳＣＰ）技术对ＨＣＶ基因变异进行研究，发现在同一家庭内的成员间ＨＣＶｃＤＮＡ的单链构象一致，但不同家庭的成员间ＨＣＶｃＤＮＡ的单链构象呈现多态性。表明该村近４年来ＨＣＶ感染明显增高主要由家庭成员传播所致。ＳＳＣＰ分析比基因分型更适用于ＨＣＶ感染的分子流行病学调查。

Objective: To study the intrafamilial transmission of HCV infection. Methods: Fouryear followup and molecular epidemiologic investigation of HCV infection in a village was carried out. The diversity of HCV core region was analysed by reverse transcription nested polymerase chain reaction, Okamoto genotyping method, and single strand conformation polymorphism analysis (SSCP). Results: The incidence of positivity of antiHCV andHCVRNA raised from 21.30% (75/352) to 43.18% (152/352). There were 42 families with two or more members serological positive for antiHCV and/orHCVRNA. There were a 3.46fold increase of intrafamilial propagation of HCV infection in the past 4 years. HCV genotyping by Okamoto method showed that 90.67% (136/150) belonged to Type 1b/Ⅱ, two cases (1.33%) belong to type 2a/Ⅲ and three cases (2.00%) were co-infection of both types. Comparison of SSCP patterns revealed that the SSCP of HCV cDNA was identical among members of the same family, but the single strand conformation of HCV cDNA exhibited polymorphism patterns in different families. Conclusion: The results indicate that the cause of marked increase of HCV infection rate in this village in a 4-year period is mainly because of intrafamilial propagation. SSCP is more feasible for molecular epidemiologic investigation of HCV infection than genotyping.