[Molecular epidemiological and clinical feature of human metapneumovirus in children with acute lower respiratory tract infection in Changsha area from 2007 to 2011].

OBJECTIVE: To understand the epidemiological characteristics of human metapneumovirus (hMPV) infection in children with acute lower respiratory tract infection (ALRTI) in Changsha area, China. METHODS: A total of 2613 nasopharyngeal aspirate (NPA) specimens were collected from hospitalized children with ARTIs between September 2007 and February 2011 (a period of 3.5 years) in Changsha area, Hunan Province, China. Respiratory specimens were screened for hMPV M gene by reverse-transcription polymerase chain reaction (RT-PCR). All RT-PCR positive' amplification products were confirmed by sequencing or analyzed and compared with those in GenBank known hMPV reference strain. RESULTS: hMPV was detected in 135 (5.2%) out of the 2613 children. The detected rate was significantly different between male and female (chi2 = 8.007, P = 0.003). The majority of the hMPV-positive patients (63.2%) were 0-1 year old infants. The majority of hMPV-positive patients were detected during spring season. Seasonal distribution showed that subtype A2b circulated predominantly in winter and spring, subtype B2 circulated predominantly in summer and spring. The most common genotype in 135 hMPV-positive patients were A and B in human subjects in Changsha. The predominant genotype of hMPV changed over the 3.5 year study period from genotype A2b to combined A2b and B2, and to B2. The 66 (48.9%) out of the 135 hMPV-positive patients were found to be co-infected with other respiratory viruses, and human bocavirus (HBoV) was the most common additional respiratory virus. CONCLUSION: These data suggest that some cases of acute lower respiratory infection in young children in Changsha area are related to hMPV and the majority of children infected with hMPV were less than 1 years old, the detected rate of boys was higher than that of girls. It circulated predominantly in spring. The subtype A2b genetic lineage and the subtype B1 genetic lineage of hMPV were revealed alternately in human subjects in Changsha area and the hMPV exhibited high co-infection rate with other respiratory viruses.