深圳市输入性基孔肯雅热病例的流行病学和病原学特征分析

Analysis on the epidemiology and etiologic characteristics of first imported Chikungunya fever case in Shenzhen in 2010

目的对深圳市2010年首例基孔肯雅热疫情及病原学特征进行分析。方法调查分析流行病学特点；对疑似患者血清标本采用ELISA和荧光PCR方法分别检测病毒IgM、IgG抗体和核酸，并用BHK-21细胞分离病毒。采用RT—PCR方法扩增病毒结构蛋白基因后进行序列测定，并与不同国家和地区的基孔肯雅毒株进行同源性比较。结果深圳市2010年10月报告的一起基孔肯雅热疫情为输入性病例。从患者血清标本中检测到病毒IgM抗体和核酸，并首次成功分离到基孔肯雅病毒，将其命名为CHIKV—SZ1050。深圳市基孔肯雅病毒分离株SZ1050与CHIKV非洲原型株S27-African、我国广东省2010年暴发疫情株GD05／2010、印度2010年流行株TN06310在E1基因上核苷酸同源性分别为98．2％、98．3％和98．7％。进化树显示SZl050株与2010年中国分离株GZ1029亲缘关系最近，其次为印度2010年流行株TN06310，属于ECSA基因型。结论从病原学、血清学和分子生物学特征上均证实该例基孔肯雅热输入病例是由基孔肯雅病毒ECSA基因型引起，病毒遗传特征与印度地区流行CHIKV-致，输入病例未引起继发病例。

Objective To study the epidemiology and the etiology characteristics of first imported Chikungunya fever case reported in Shenzhen city in 2010. Methods Data on descriptive epidemiology was collected to study the characteristics to the epidemic. The serum sample collected from the suspect Chikungunya fever case was detected for IgM, IgG by ELISA and Chikungunya virus nucleic acid by real- time RT-PCR. The samples were further inoculated in BHK-21 cells for virus isolation. Structural polyprotein gene （ C-E3-E2-6K-E1 ） of isolated virus strain was amplified by RT-PCR and sequenced to construct homology comparison and phylogenetic tree of E1 gene of Shenzhen CHIKV with the strains isolated from other areas. Results The case was laboratory confirmed imported Chikungunya fever cases in Shenzhen on October 2010. IgM antibody and RNA of Chikungunya virus were detected in the serum sample. Chikungunya virus named CHIKV-SZ1050 was successfully isolated from the serum sample for the first time. The homology of nucleotide sequence of E1 gene of SZ1050 with African prototype $27 strain, GD05/2010 strain, TN06310 strain were 98.2% , 98.3% and 98.7% , respectively. The phylogenetic tree indicated that SZ1050 was most close to GZ1029 strain, next to TN06310 strain. The isolated Chikungunya virus belonged to genotype ECSA. Conclusion The virological, serological and molecular features showed that the imported case of Chikungunya fever in 2010 was caused by CHIKV ECSA genotype and genetic characteristics of the SZI050 virus strain are consistent with CHIKV popular in India. This imported case did not cause the secondary cases.