Abstract：Objective To investigate the epidemic and profiles of respiratory viruses based on the sentinel surveillance on febrile respiratory illnesses (FRI) in Hunan Province so as to provide scientific evidence for prevention, control and clinical diagnosis and therapy of FRI . Methods We collected nasal/throat swabs, bronchoalveolar lavage fluid and sputum samples from inpatients with FRI from January 2012 to December 2014. The 9+7 multiplex polymerase chain reaction (multiple-PCR) assay for rapid identification of respiratory virus types/subtypes based on capillary gel electrophoresis was used to detect the nucleic acid of 8 viruses including influenza virus (Flu), respiratory adenovirus (AdV), respiratory syncytial virus (RSV), human rhinovirus (hRV), parainfluenza virus (PIV), human metapneumovirus (HMPV), human bocavirus (hBoV) and human coronavirus (hCoV).The case information and test results were analyzed by SPSS17.0 software. Results A total of 961 respiratory tract specimens were collected from inpatients in two sentinel hospitals from January 2012 to December 2014, including 595 specimens (61.91%) from male cases and 366 (38.09%) from female ones. Among the 961 samples detected by PCR, 456 were positive for viral nucleic acid, with the positive detection rate of 47.45%. No statistically significant difference was found in the positive detection rate between males and females(P>0.05). All the inpatients were divided into seven age groups, and the positive detection rates of viral nucleic acid in each age group were as follows 52.80% for group of < 1-year old, 66.53% for 1-2 years old, 49.86% for 2-5 years old, 25.56% for 6-15 years old, 11.11% for 16-49 years old, 17.39% for 50-64 years old and 19.40% for 65- years old. Among the 456 viral nucleic acid positive specimens, 48 indicated mixed infections and 408 indicated single infection. Among the detected respiratory viruses, AdV (25.90%), RSV (21.31%) and Flu (17.73%) accounted for the largest proportion of the profiles, followed by hRV (14.14%), PIV (11.75%), HMPV (4.78%) and hBoV (3.98%). Only two samples were detected to be hCoV nucleic acid positive. Statistically significant difference in the pathogenic profiles of respiratory viruses was not found between the male cases and female ones(P>0.05),but was found among different age groups(P<0.05). Among the inpatients aged ≤ 2 years, Adv (29.36%) and RSV (23.02%) were the dominant detected viruses, followed by PIV (13.10%), hRV (11.90%) and Flu (11.11%). Among the inpatients aged 2-5 years, AdV (34.02%) accounted for the largest proportion of the detected viruses, followed by hRV (18.56%), Flu (18.04%) and RSV (15.46%). Among inpatients aged 6-15 years, Flu (31.43%) and PIV (34.29%) were the main detected viruses, followed by AdV (17.14%) and hRV (14.29%). Among inpatients aged 16-49 years, only Flu was detected. Among inpatients aged ≥50 years, Flu (68.41%) accounted for the largest proportion of the detected viruses, followed by PIV (10.53%), HMPV (10.53%) and RSV (10.53%). There were two epidemic peaks for Flu and AdV, which appeared in summer and winter/spring, while the epidemic peaks of RSV and hRV appeared in winter/spring and in autumn/winter respectively. Conclusions The 8 respiratory viruses under surveillance are the important pathogens causing severe acute respiratory infections in the inpatients. Children aged ≤ 5 years and the elderly aged ≥ 65 years might be the main susceptible populations. RSV, AdV and Flu may be the main pathogens resulting in viral respiratory infections in children, while Flu may be the main pathogen inducing viral respiratory infections in adults. Therefore, it is necessary to conduct further surveillance and more in-depth investigation targeted on the prevention and control of the febrile respiratory illnesses caused by these viruses.
2016, Vol. 23 
