A Clinical Study On The Infection Of HMPV And RSV In Fuzhou Area

【Objective】Human metapneumovirus (HMPV) is a newly discoveried pathogen associated with respiratory infections. Respiratory syncytial virus (RSV) is a common cause of respiratory illness. The aim of this study was to investigate the pathogenicity of the HMPV in patients with respiratory infection in Fuzhou areas, and comparing their epidemic features and clinical characteristics with those of infected with RSV.【Methods】A total of 153 patients with respiratory tract infection were observed, aged from 27 days to 96 years old, from Dec. 2005 to Apr. 2007 in Fujian Provincial hospital. In these patients, 91 were male and 58 female, 119 were children and 34 adults. HMPV was detected by a nested RT-PCR focusing on the M gene, and RSV was tested by RT-PCR for the N gene. Parts of PCR products were randomly selected for sequencing analysis.【Results】 1,In the 153 specimens, 32 (19.61%) were positive for HMPV, including 22 Children (mean age 4.58±3.35 years) and 10 adults, and 26(17.0%) were positive for RSV. Children with HMPV were older than those with RSV (mean age 2.65±2.65 years) (P＜0.05). The youngest of the HMPV positive patients was 8 month old. As for RSV, it was 27 days after birth. Positive rate for HMPV detection was 25.8% from Dec. 2005 to Apr. 2006, which was higher than that of the period from Dec. 2006 toipr. 2007(15.2%) (P＜0.05). On the contrary, the positive rate of RSV from Dec. 2005 to Apr. 2006(12.4%) was lower than that of the period from Dec. 2006 to Apr. 2007(30.4％) (P＜0.05). Compare with the male, there was a higher infectious rate of HMPV in the female(P＜0.05), the same was RSV.2,Eight of these 153 specimens were HMPV / RSV co-infections. Five of them were female, five of them were adults.3,HMPV infection was associated with pneumonia or acute bronchiolitis (34%). In the 32 patient with HMPV infection, 40% had cough, 21% were congesting in portio pharyngis, and 34% had a fever. Similarly, pneumonia or acute bronchiolitis was often existed in patient infected by RSV (46%). The clinical manifestations in the RSV-positive patients were as follow: cough (60%); Congested pharynx (30%); febricity (19%).4,Nucleotide sequences of three 432bp-PCR-product were 100% identical and summited to GenBank (the accession No. DQ887758). They were closely related to HMPV partial M gene in the GenBank. Similarity of HMPV partial M gene with HMPV M gene published at nueleotide levels varied from 85% to 99%. The amino acid indentity of HMPV part of M gene with other published HMPV was 93.0%～100%. Phylogenetic tree analysis of nueleotide sequences revealed that the three isolates clustered in HMPV strain BJ1816 which belonged to genotype A. The nucleotide sequences of the two 266bp-PCR-product for RSV were completely similar and 97% identical to the N-gene fragment of RSV strain BJ9149 (GenBank accession No. DQ780564.1).【Conclusion】Both HMPV and RSV infection are the major causes of respiratory tract infection in the different stage of individuals in Fuzhou area. Only one genotype of HMPV circulated during the period. Our study also indicates that patients with HMPV or RSV infection may have similar symptoms and signs. Moreover, HMPV and RSV can be present as a co-infection.