Study On Viral Etiology Of Acute Respiratory Tract Infection In Children

ObjectiveTo investigate the molecular epidemiology feature of respiratory virus in children with acute respiratory tract infection(ARTI) in Nanjing. And to mainly research the molecular epidemiological and clinical feature of human adenovirus(ADV) in children with acute respiratory tract infection in Lanzhou area and Nanjing area of China.Subjects and methods1. Nasopharyngeal aspirates or nasopharyngeal swab were taken from 642 outpatients or hospitalized pediatric patients with ARTI at the Children Hospital of Nanjing,Jiangsu Province, between August 2009 and July 2010,and 359 pediatric patients with ARTI at the First Hospital of Lanzhou University.Gansu Province,between December 2009 and November 2010.2.642 respiratory specimens from Nanjing were tested for the 12 common respiratory viruses (ADV, HBoV, RSV, HRV, IFVA, IFVB, PIVI-3, HMPV, HCoV-HKU1 and NL63)by PCR or RT-PCR.772 respiratory specimens from Nanjing and Lanzhou were rapidlly tested for ADV using real-time PCR method. Then we typed the ADV positive specimens by analyzing the hexon genes of ADV,using nested PCR method.3. Epidemiological and clinical feature of each virus were analyzed, especially for ADV.Results1. The virus positive rate was totally 62.5%(401/642), of which, HRV detection rate was the highest (20.4%), followed by RSV (19.3%), PIV3 (16.0%). HBoV (9.5%), HMPV (5.5%), IFVB (4.2%), ADV (3.9%), IFVA (1.9%), NL63 (1.1%), HKU1 (0.8%), PIV1, PIV2 were negative in all the specimens tested.Among the 401 positive specimens, the median age of the patients was 8.6 months,ranged from 1 month to 134 months.92.3% patients with viruses infection were under 5 years of age.There were statistically significant difference in respiratory viruses detection rate between different age groups.With the increasing of age. the virus detection rate trended to decline. There were remarkable age distributions of HBoV. RSV. IFVB and PIV3. Respiratory viruses were detected throughout the year in Nanjing area. There were statistically significant difference in respiratory viruses detection rate between four seasons. The detection rate were highest in winter and lowest in autumn. There were remarkable seasonal distributions of ADV,HBoV,RSV,IFVB,PIV3 and HMPV. There were statistically significant difference in respiratory viruses detection rate between different clinical diagnostic groups. The detection rate of HBoV,RSV,HRV,IFVA,PIV3,HMPV were significantly different between different clinical diagnostic groups. Among the 401 positive specimens,27.2% specimens were co-infected with other respiratory viruses.2. ADV was detected in 67 (8.7%) of the 772 pediatric patients.The detection rate was 7.8% in Lanzhou area, and 9.4% in Nanjing area. There were statistically significant difference in ADV detection rate between different age groups.The peak of the detection rate was in the 2-3 years age group in Lanzhou area, and in the 1-2 years age group in Nanjing area. ADV could be detected throughout the year in two areas. No significant differences were found between four seasons. But the peak of the detection rate was in May in Lanzhou area, and in July in Nanjing area. ADV mainly cause lower respiratory tract infection in children.3. Among the 67 ADV positive specimens,the typing rate was 100%. The ADV species C was the dominant species in two area.especially in Lanzhou area. Of which,type 6 and type 1 was the dominant lineage in Lanzhou area and Nanjing area,respectively. In the ADV species B, type 7 and type 3 was the dominant lineage in Lanzhou area and Nanjing area.respectively.Conclusion1. Respiratory viruses were important pathogens of acute respiratory tract infection in children in Nanjing area. HRV was the leading pathogen.followed by RSV and PIV3. 92.3% patients with viruses infection were under 5 years of age. With the increasing of age, the virus detection rate trend to decline. The peak of the detection rate of respiratory viruses was in winter.2. No significant differences were found in ADV detection rate between Lanzhou area and Nanjing area. There were statistically significant difference in age distribution in two area,but not in seasonal distribution.3. The ADV species C was the dominant species in two area,especially in Lanzhou area. Of which,type 6 and type 1 was the dominant lineage in Lanzhou area and Nanjing area,respectively. In the ADV species B. type 7 and type 3 was the dominant lineage in Lanzhou area and Nanjing area,respectively.