Molecular Epidemiological And Clinical Features Of Respiratory Virus In Children With Acute Respiratory Track Infection

Backgroud:There is limited epidemiological data about human respiratory syncytial virus(HRSV) and AdV infection in China, especially about the prevalence and clinical and molecular characterization of subgroups or serotype of HRSV and AdV in children with acute respiratory tract infections(ARTIs). Relationship between RSV subgroups and severity of disease has not been reported in China.Objectives:To investigate the prevalence and clinical and molecular Characterization of HRSV and AdV in Chinese children with ARTIs.Methods:894 nasopharyngeal aspirates(NPA) were collected from 894 children younger than 14 years old with ARTIs from December 2006 to March 2009. All specimens were screened for HRSV by reverse transcription-polymerase chain reaction (RT-PCR) of partial nucleocapsid(N) gene Classification of HRSV strains were achieved by sequencing C-terminal hypervariable regions(HRV2) of G protein. The demography and clinical information of the patients were collected for statistical analysis.Adenovirus was isolated from 1169 nasopharyngeal aspirates(NPA) collected from children younger than 14 years with acute respiratory tract infection in the first hospital of Lanzhou university from November 2006 to November 2009. Specimens were screened for AdVs by polymerase chain reaction (PCR) of hexon gene.Results:38.14% samples(341/894) were positive for HRSV by RT-PCR 227(67%) RSV-positive specimens were subtyped by HRV2 sequence. Phylogenetic analysis reveals that 60% of the 227 strains was GA2.34.4% was BA.4.8% was GB2.0.4% was GB3. The deduced amid acid and the subgroup B were highly diverse. Between genotype BA and GA2 positive patients no statistical differences were found in epidemiological or the disease severity using univariate analysis.A total of 74(6.33%) of 1169 specimen were positive for adenoviruses. of the 74 AdVs positive cases, type 3(58/74) was the most frequent detected, followed by type 11-like(10/74), type2(2/74). type7(2/69), type 6(1/74).and type 1(1/74). Ad-3 account for 78.38% of adenovirus isolates. The novel genetype Ad-55 were detected. the incidence of AdVs infection peaks in who were 3-7 years old. but a relatively high infection rate(3.293%) of AdVs were observed in infants younger than 6 months. The most common clinical diagnosis was URI. fever and cough was the most common syndrome.Conclusion:HRSV was the most important viral pathogen in Chinese children with ARTIs, Four genotypes(GA2. BA, GB2 and GB3) circulated locally and the predominant genotype may shift with annual or not. Subgroup B displayed more variation and greater potential for divergence in the HRV2 than Subgroup A. HRSV may evolve in a complex pattern of the transmission and circulation with a global distribution. Furthermore no relationship between clinical severity and HRSV genotypes was found.multiple adenovirus serotype cocirculated in Lanzhou city. China. Ad3 was predominated during November.2006 to November.2009. Ad55. the novel HAdV was found exist in Lanzhou citv China. no fixed rhvthm of the adenovirus season could be identified.