云南中缅边境一起输入性登革热暴发的分子流行病学研究

目的调查云南中缅边境一起输入性登革热流行状况及其流行病毒株的分子流行病学特点。方法采集医院就诊和口岸入境人员中登革热、疑似登革热和不明原因发热患者血清标本并进行流行病学调查，采用ELISA检测登革病毒IgM抗体，RT-PCR检测登革病毒核酸，核酸阳性标本进行登革病毒PrM．C和NS，区的基因核苷酸序列测定和分析。结果2008年7—11月在云南省瑞丽市共采集急性期患者血清标本103份，经登革病毒IgM抗体和核酸检测，49例确诊为登革热。其中除1例为当地感染病例，其余48例均为输入性病例，其中18例来自缅甸木姐市居民，30例为中国居民到缅甸经商或务工返回后发病者。从缅甸输入病例血清中获得2株病毒(RLB61和RLC31)的PrM．C和NS，区基因核苷酸序列，同源性和系统进化分析表明，RLB61株为登革l型病毒，RLC31株为登革3型病毒，与东南亚登革病毒流行株具有较近的亲缘关系。结论经血清学和分子流行病学证实瑞丽市边境地区发生输入性登革热暴发，并间接证实缅甸木姐市2008年存在登革l和3型病毒流行。

An outbreak of imported dengue fever from Myanmar to the border of China,with its viral molecular epidemiological features

Objective To understand the epidemiologic characteristics of dengue fever, imported from Myamnar to the border of Yunnan province, China. Viral molecular epidemiologic features were also studied. Methods Questionnaires were used on each diagnosed, suspected dengue fever, case or unknown cases with fever when coming from Myanmar entering the port and hospitals in Ruili city of Yunnan province. Serum samples of these patients were collected to detect IgM antibody against dengue virus and RT PCR assay. Homology and phylogenetic tree based on the whole nucleotide sequence of PrM-C and NS5 gene of dengue virus were further analyzed. Results A total of 103 sera were collected from patients at acute stage in Ruili city in July to November 2008. Among them, 49 cases were confirmed for dengue fever according to IgM and nucleic acid testings. Except one, other 48 cases were all imported into Ruili, from Myamnar. Of those, 18 patients were residents from Mujie city of Myanmar and hospitalized in Ruili and the rest 30 patients were Chinese citizens who had finished business and returned from Myanmar. Two isolates of serum samples from the imported cases were identified and both homology and phylogenetic analysis were performed, using the nucleotide sequences of PrM and NS, genes. They were divided into dengue type I (RLB61)and dengue type 3 (RLC31)and were closer to the dengue virus strains isolated from Southeast Asia countries. Conclusion it is confirmed that an epidemic of dengue fever which was imported from Myanmar to Ruili city of Yunnan province, China. Evidence also showed that both type I and II1 epidemic strains of dengue virus did exist in Mujie city of Myanmar in 2008.