Epidemiological Characteristics Of Children’s Respiratory Tract Viral Infection During 2012 To 2014,chongqing

Objective The current study is carried out to understand the spectrum of pathogens of acute viral respiratory infection as well as find the prevalence and genetic characteristics of some common respiratory viruses and emergering respiratory viruses in children in Chongqing area, and to provide the information for the treatment and prevention of the children with acute viral respiratory tract infection in this and other regions.Content 1.During two years from June, 2012 to May, 2014,the major study includes the rate of respiratory virus positive detection, the rate of combined-infection, the characteristic of time distribution, the distribution of age and sex,the relationship between respiratory diseases and the clinical symptoms of hospitalized children in respiratory tract infected children in Chongqing area.2.During these two years from June, 2012 to May, 2014, we studied the infection of HRV in in children with respiratory tract infections in Chongqing area. The HRV positive samples were classified, and the positive rate, co-infection rate, time distribution, age and sex distribution, clinical symptoms and characteristics of genetics of HRV-C were researched.3.During the two years from June, 2012 to May, 2014,we studied the epidemiological characteristics of WU and KI polyomavirus in children with respiratory tract infection in Chongqing.Object The samples were collected in the children’s Hospital affiliated with Chongqing Medical University from June, 2012 to May, 2014. The case definition was sick children with acute respiratory tract infection and clinical manifestations.Nasopharyngeal aspirate samples were collected for research.MethodsThe samples were collected from patients in accordance with case definition. The nucleic acid extraction, reverse transcription, PCR, fluorescence quantitative PCR were applied to detect and classify the common and the emergering respiratory viruses, including RSV, IFV, PIV, ADV, HBOV, MPV, HRV/HEV, COV, WUPy V, KIPy V, and SAFV. Parts of the virus were amplified by PCR and sequenced to acquire the gene sequence. The methods of statistical analysis and gene sequence analysis were applied for the epidemiological and genetic characteristics of the virus.Result 1.The surveillance of respiratory virusesIn the study, totally 994 hospitalized children with ARTI were recruited from Jun 2012 to May 2014. The repiratory viruses detection rate was 76.46%. The highest detection rate was RSV(295, 29.68%), followed by PIV(260, 26.16%), 、HRV/HEV(187, 18.81%)、IFV(110, 11.07%)、WUPy V(107, 10.76%)、HBo V(79, 7.95%)、HAd V(39, 3.92%)、MPV(29, 2.92%)、HCo V(15, 1.51%)、KIPy V(9, 0.91%) and SAFV(6, 0.60%). The coinfection rates among all the resipratory viruses were 46.15~80.00%. The peak of RSV was at autumn and winter, IFV and WU at spring and summer, while HRV/HEV had higher detection rates all the year. The detection rates of HBo V or HRV/HEV in boys was higher than those in the girl, respectively. The detection rate decreased along with the increasing age. However, IFV-A had a higher detection rate at the age group of 2~5 years old. Cough was the main sydrome of the children with ARTI, followed by sputum, fever, diarrhoea, difficulty breathing and runny nose. Among the four ARTI diseases, the children diagnosed as bronchitis had a highest detection rate, followed by asthma, pneumonia and upper respiratory tract infection. The top three respiratory viruses were PIV, RSV and IFV in the children with bronchitis, and RSV, PIV, and HRV/HEV with asthma or pneumonia or upper respiratory tract infection.2.HRV Totally 107 children were detected to HRV postive infection, with the detection rate of 10.76%, including 63 HRV-A, 8 HRV-B and 36 HRV-C. No significant differences of the distribution of HRV subtypes were found in the groups of age and sex. HRV-C caused more sputum compared to HRV-A and HRV-B. The coinfection proportions of three HRV types were 44.44~62.50%. The top three coinfection respiratory viruses of HRV-A and HRV-C were RSV-B, PIV3, and WU. The 20 HRV-C types were detected in the study, and the top two were HRV-C6 and HRV-C38, different from the previous three years(HRV-C2). Three sequences were detected, similar to the CQ4290 strain with the homology of 92.15~96.71%.3.WUPy V and KIPy V Total 57(23.27%) Wu Py V were detected in spring and 34(27.10%) in summer, suggesting significant differences of the season(P<0.001). A subpeak of WUPy V were detected during June-August 2012, while the detection rate obviously inceased during April-June 2013, suggesting an outbeak of WUPy V infection at this period. The proportion of WUPy V single infecion was 27.10%(29/107). Among the 29 children, 26 was diagnosed as pneumonia( 5 severe), 5 as upper respiratory tract infection, 2 asthma and 2 bronchitis. PIV3 was the most coinfection virus with WUPy V.Among the 9 KIPyV infection, 2(22.22%) was single infection and diagnosed as pneunomia and bronchitis. Four children also infected with HRV/HEV. We got 84 VP2 gene sequences of WUPy V and 8 VP1 gene sequences of KIPy V, which were similar to the sequences at home and abroad with the homology more than 95%.Conclusion 1.Epidemical characteristics of respiratory viruses(1)Respiratory viruses were the most common pathogens caused the children’s ARTI in the Chongqing area, especially for RSV, PIV,HEV/HRV, IFV and WUPy V.(2)RSV-B has become the predominant subtype of RSV in Chongqing area.(3)WUPy V may have an outbreak during June-August 2013.2.HRV(1)HRV was the important pathogen caused the upper respiratory tract infection, mainly including HRV-A and HRV-C. All the three types of HRV had coinfection proportions with WUPy V.(2)The predominant strain type of HRV-C changed from HRV-C2 to HRV-C6 and HRV-C38. The new type detected in 2009~2012 occurred in this study.3.WUPy V and KIPyV(1)The real-time PCR method was sensitive to detect WUPy V and KIPy V.(2)WUPy V and KIPy V probably caused the children’s ARTI, even severe pneumonia.(3) The gene sequences of WUPy V and KIPy V obtained in this study had high similarity with the sequences both at home and abroad, genes in this region were relatively stable and conservative.