目的　对广东省江门地区 2 0 0 1年夏、秋季一批发热、出疹患者进行确诊 ,并从分子水平分析流行株的可能来源。方法　分别采用免疫荧光、细胞毒力、乳鼠毒力实验以及逆转录 聚合酶链反应 (RT PCR)技术进行病毒鉴定 ,并对其结构蛋白基因序列进行克隆、测序及同源性搜索。结果37份患者血清登革病毒 (DV)IgM抗体阳性率为 97% (36 37) ,IgG抗体阳性率为 59% (2 2 37) ,最高抗体滴度均可达 1∶640。所得病毒可致C6 36细胞病变 ,具有乳鼠神经毒力 ;其结构基因序列长度为2 32 5bp ,编码 774个氨基酸 ;与其他登革 2型病毒株TSV0 1、GD0 6 93、NGC、44、ThNH、0 4、GD0 8 98及S1进行比较 ,其核酸序列同源性 (% )分别为 98、96、94、94、92、92、92、91。结论　 2 0 0 1年江门地区登革热流行为登革 2型病毒感染所致 ,推测其可能是输入性传染 Objective To diagnose a group of fever and rash in summer and autumn in 2001 in Jiangmen of Guangdong Province and to analyze the possible sources of the epidemic strain at the molecular level. Methods The viruses were identified by immunofluorescence, cytotoxicity, virulence test and reverse transcription polymerase chain reaction (RT PCR) respectively. The structural protein gene sequences were cloned, sequenced and homologous searched. Results The positive rate of serum anti-dengue virus (DV) IgM antibody in 37 patients was 97% (36 37). The positive rate of IgG antibody was 59% (2 2 37). The highest antibody titer reached 1: 640. The resulting virus can cause C636 cell lesions, with the virulence of neonatal rat; its structural gene sequence length of 2 32 5bp, encoding 774 amino acids; and other Dengue 2 strains TSV0 1, GD0 6 93, NGC, 44, ThNH, 0 4, GD0 8 98 and S1, the nucleotide sequence homologies (%) were 98, 96, 94, 94, 92, 92, 92 and 91, respectively. Conclusion The dengue fever epidemic in Jiangmen area in 2001 was caused by dengue type 2 virus infection, suggesting that it may be an imported sexually transmitted infection