东莞市镇区小儿呼吸道人类偏肺病毒感染临床与分子流行病学特征

Clinical and Molecular Epidemiologic Characteristics of Human Metapneumovirus Infection in Children in Township of Dongguan City

目的了解东莞市镇区小儿呼吸道人类偏肺病毒(hMPV)感染的临床与分子流行病学特征。方法收集2007年2-10月东莞市石碣医院儿科门诊及病房7岁以下呼吸道感染患儿呼吸道分泌物标本340例,采用反转录-聚合酶链反应(RT-PCR)检测hMPVF基因,应用多重PCR检测呼吸道合胞病毒A、B型(RSVA、B型),流感病毒甲、乙型(Flu-A、B型),副流感病毒1、2、3型(PIV1、2、3型)。并随机挑选4例hMPV阳性者PCR产物行基因测序分析。结果340份标本中hMPV阳性者32份(9.41%),其中在阳性标本中5例并RSV感染,2例并PIV3型、2例并Flu-B型。2-4月份检出阳性率高于5-10月份。32例hMPV感染阳性患儿平均年龄5.97个月,临床表现以发热、咳嗽、喘息为主,hMPV感染患儿临床表现与其他常见呼吸道病毒感染者无显著性差异(P>0.05)。32例hMPV阳性患儿诊断下呼吸道感染30例,占阳性标本的93.75%,急性上呼吸道感染2例(6.25%)。4例PCR产物基因测序分析与GenBank序列同源性87%～99%。hMPV PCR产物基因序列进化数分析显示其属于2个不同的基因型,其中A基因型3例,B基因型1例。结论hMPV是小儿呼吸道感染一种重要的病原体,小儿呼吸道hMPV感染发病率在2-4月份较高,其临床表现以咳嗽、发热、喘息为主。东莞地区小儿呼吸道感染中hMPV存在A、B2个不同基因型,以A基因型较常见。

Objective To explore clinical and molecular epidemiologie characteristics of human metapneumovirus（hMPV） infection in children in township of Dongguan city. Methods The total RNA were extracted from 340 specimens which had been collected from children less than 7 years old from Feb. to Oct. 2007 in Shijie Hospital of Dongguan City. During the study, the hMPV was screened by reverse transcription- polymerase chain reaction（ RT- PCR）. The conventional respiratory viruses including respiratory, syncytial virus A and B（ RSV - A, RSV- B）, influenza A and B（ Flu- A, Flu- B）, parainfluenza 1,2,3 （PIV -1, PIV- 2, PIV- 3 ） were detected by multiplex PCR. PCR products which were visualized by 20 g/l, agarose gel electrophoresis. Four positive PCR products selected randomly were sequenced and the sequences of the nucleotides were compared with those in the GenBank and analyzed for their homology. Results Among those 340 specimens for hMPV ,32 （9.42%） showed the predicted 450 bp PCR products in agarose gel electrophoresis. In these hMPV positive sample,some sampies were double infections including 5 cases co - infected with RSV ,2 cases with PIV -3 and 2 cases with Flu - B. The positive rate between Feb. and Apr. was higher than other months. The mean age of the positive was 5.97 months,and the main clinical symptoms were as follows： cough,tebricity,and gasping. Comparing the infection of hMPV with other respiratory viruses, no differences had been found in both clinical symptoms and physical signs among the hMPV positive children （ P 〉 0.05 ）. Thirty eases of the 32 children showed lower respiratory tract infection,which accounted for 93.75% of these positive specimens. Of the 32 patients, there were 2 cases with upper respiratory, tract infection, which was 6.25% of these positive specimens. The sequence homology of 4 PCR -product sequencing gene analysis with GenBank was 87% - 99%. Based on genomic sequencing and phylogenetic analysis 3 cases of all hMPV sequenced strains belonged to genotype A,and 1 ease belonged to genotype B. Conclusions hMPV is a significant pathogen in respiratory infection of children,which causes non - specific clinical symptom or physical sign compared with other common respiratory viruses. Peak incidence of hMPV was found between Feb. and Apr. The main respiratory infection caused by hMPV is lower respiratory infection w＇hose symptoms are mainly cough ,fever and gasping. Two hMPV genotypes have been screened in the chihlren of l）ongguan city,and maybe hMPV genotype A dominated over genotype B.