Prevalence of human metapneumovirus in hospitalized children with respiratory tract infections in Tianjin, China

Human metapneumovirus (hMPV) has recently been recognized as an important respiratory pathogen, especially in children. At present, our understanding of the characteristics of hMPV from China is very limited. Nasopharyngeal aspirates were taken from 310 hospitalized pediatric patients. Twenty (6.5%) of them were infected with hMPV, and they all developed pneumonia. Sixty five percent (13/20) of the cases were under 12 months. Phylogenetic analysis of F gene fragments indicated that three sub-genotypes of hMPV(A2a/A2b, B1,B2) circulated in Tianjin and A2b was the predominant subtype. The Vero-E6 cell line was better than LLC-MK2 for hMPV isolation. Three hMPV strains were successfully isolated using the Vero-E6 cell line.