Isolated And The Sequence Analysis Of The N Genes Of Human Metapneumovirus In Children With Wheezing In East Guangdong

Background and objective To analyze the status of the human metapneumovirus(HMPV) in wheezing children in East Guangdong and the clinical characteristic of the diseases with HMPV infection. To anlyze the sequence of the N genes of HMPV.Material and methodsMaterial: From June 1,2006 to June 1,2007,a total of 340 nasopharyngeal secretions or throat swab samples(240 from children with wheezing, 100 from health children) were collected from children with wheezing.Methods: 1. respiratory syncytial virus (RSV), human bocavirus(HBOV),influenza virus type A, B(IV A, B), Rhinovirus(RV),parainfluenzavirus type 1,3 (PIV1, 3) and adenovirus(ADV) were investigated by multiplex polymerase chain reaction (PCR). 2. The viral nucleic acid of HMPV N gene of 323 samples were amplified by RT-PCR, and six HMPV N gene positive PCR products were randomly chosen for purified and sequenced. Nucleotide sequences alignment and phylogenetic analysis were performed with DNAstar software. The clinical data of the children with HMPV infection were analyzed.Results1.Viruses were detected in 101 of all cases(42%), with RSV in 41(41%) the most frequent,followed PIV3 in 18(18%), RV in17 (17%), IV A in 16(16%), PIV1 in13 (13%),HMPV in 12(12%), ADV in 5(5%), HBOV in 4(4%)and. Mixed viral infection was detected in 15 cases.2.The positive rate of the HMPV infection identified from 240 children with wheezing was 5%(12/240). The positive rate of HMPV from the negative samples of other virus was 7.9%. HMPV was significantly more prevalent in March and April(5/12). Six HMPV N gene fragments of sequence were closely related to HMPV in the GenBnk. Similarity of HMPV partial N gene with HMPV N gene published at nucleotide levels varied from 80.8 to 98.4. Phylogenetic tree analysis of nucleotide sequences revealed 2 different genotypes. All 12 HMPV-posotive patients suffered from fever, cough and wheeze. The clinical diagnoses of the HMPV-posotive patients were wheezy pneumonia (four patients), bronchiolitis(eight patients).3.None of the throat swabs 100 cases from healthy subjects tested HMPV-positive. 1 PIV3, 3 RSV and 4 RV had detected, None of other virus had detected.Conclusions HMPV is an important viral pathogen in children with wheezing in East Guangdong, however its clinical signs were not specific. HMPVs of different genotypes may co-circulate in children in East Guangdong.