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There are limited data on the prevalence and clinical and molecular characterization of human respiratory syncytial virus (HRSV) in children with acute respiratory tract infections (ARTIs) in China. From December 2006 to March 2009, 894 nasopharyngeal aspirates (NPAs) were collected from children under 14 years of age with ARTIs. Samples were screened for HRSV and genotyped by reverse transcription-PCR (RT-PCR) and sequencing. Demographic and clinical information was recorded. A total of 38.14% (341/894) of samples were positive for HRSV. Phylogenetic analysis revealed that 60.4% of the selected 227 RSV strains were GA2, 34.4% were BA, 4.8% were GB2, and 0.4% were GB3. A total of 40.47% of all of the RSV-positive samples were coinfected with other respiratory viruses, and adenovirus was the most common additional respiratory virus. No statistical differences were found in the frequency of diagnosis and symptoms between the coinfection group and monoinfection group. Additionally, no statistical differences were found in epidemiological characterizations or disease severity between genotype BA- and GA2-positive patients, except for a greater frequency of lower respiratory tract infections (LRTIs) (mostly bronchitis)with BA. HRSV is the most important viral pathogen in Chinese children with ARTIs. Four genotypes (i.e., GA2, BA, GB2, and GB3) circulate locally, and the predominant genotype may shift between seasons. Coinfection with other viruses does not affect disease severity. HRSV genotypes were not associated with different epidemiological characterizations or disease severity.

Human rhinovirus C (HRV-C) is a newly identified genotype of HRV found in patients with respiratory tract infections (RTIs); however, its epidemiological profile and clinical characteristics are not well understood. In this study, Chinese children with RTIs were screened for HRV-C and their epidemiological and clinical characteristics were analyzed. From December 2006 to November 2007, 406 nasopharyngeal aspirates from children younger than 14 years of age with RTIs were screened for HRV and other common respiratory viruses by PCR or reverse transcription-PCR. Two-hundred twenty-four (55.2%) of the specimens were infected with at least one virus, including 53 patients with HRV (13%). HRV-A, HRV-B, and HRV-C were detected in 22, 12, and 19 specimens, respectively. HRV-C was detected mainly from December 2006 to April 2007 and from October to November 2007, with peaks in December and April (10/19). Acute upper respiratory infection and bronchopneumonia were observed in 53 and 37% of the cases, respectively. The most common symptoms were cough (82%), runny nose (53%), and fever (37%). Wheezing and bronchiolitis were less common in patients infected with HRV-C than in those infected with respiratory syncytial virus (RSV). Partial sequencing of the genes coding for VP4 and VP2 revealed that the HRV-C strains were 56 to 62% identical at the amino acid level to HRV-B and HRV-A reference strains and 80 to 99% identical to HRV-C reference strains. In conclusion, HRV-C is an important cause of RTIs in children, and highly diversified strains of HRV-C are prevalent in China. HRV-C may produce different epidemiological features, and patients infected with HRV-C may exhibit different clinical features from patients infected with RSV or HRV-A/B.

The KI and WU polyomaviruses were found in 11 (2.7%) and 17 (4.2%) of 406 nasopharyngeal aspirates, respectively, from children with acute respiratory tract infection (ARTI). The phylogenetic analysis indicates that they are all in the same cluster as the prototype strains. Our findings suggest that they are common in children with ARTI in China.