A Study On Viral Etiological Of 489 Hospitalized Chidren Children Aged Less Than 5 Years With Aevere Acute Respirstory Tract Infection In Chenzhou

Objective We conducted a case-control study on viral etiological of hospitalized children who are younger than 5 years with severe acute respiratory tract infection(SARI) in Chenzhou from 2013 to 2014,to understand the virus epidemiological characteristics of this region,to provide reference for clinical diagnosis,disease prevention and control.Method 1.The study selected the children as cases who hospitalized with ASRTI in the first people’s of Chenzhou from July 2013 to June 2014,and the children as controls who are in the hospital for a healthy examination or a operation at the same time,the ratio of the cases to controls is 2:1.2. Nasopharyngeal and oropharyngeal swabs of participants were tested for 18 kinds of respiratory viral pathogens and 9 kinds of bacterial pathogens and Candida albicans,Chlamydia pneumonia and Mycoplasma pneumoniae using real-time fluorescence polymerase chain reaction(RT-PCR).Used Nested-PCR to detecte ADV-positive specimens, The HMPV-positive specimens were detected by the final products were sequenced-based typing.3.Analysis of the epidemiological characteristics and clinical diagnosis of RSV、HMPV、IFV-A、IFV-B、IFV-C、ADV、HBo V、PIV1-4.Result1.After screening according to the inclusion criteria and exclusion critera there are 489 cases and contronls.Among the 489 case patients enrolled,at least one virus was detected in 359(73.41%), RSV was the most frequently detected virus(27.61%),followed by ADV 9.81%、HRV9.40%、IFV-A 8.38%、PIV2 7.15%、HMPV 5.31%、PIV3 4.90%、PIV1 4.70%、IFV-B 4.08%、HBo V 3.88%、OC43 3.06%、IFV-C 2.24%、HKU1 1.43%、EV 1.02%、NL63 1.0%、229E 0.81%、PIV4 0.81%,and no HPe V was detected.Among the 244 control subjects enrolled,at least one viruse was detected in 65(26.64%) and no PIV2, IFV-B, HKU1, PIV4, HPe V were detected,the most commonly detected viruse were HRV(10.25%).The overall positive rate of viral detection of case patients was higher than control subjects(P=0.000).Besides HBo V,IFV-C,PIV4,positive rate of other viral detection of case patients was higher than control subjects among the 11 kinds of viral.2.On age distribution of case patients, the detection rate was significantly higher in 12 to 35 months old children than 1 to 5 months children and 36 months to 5 years(P=0.000). The IFV and HBo V detection rate was highest in children among 3 to 5 years, RSV mainly detected in 1 to 3 years old children,and HMPV and PIV I-IV detection rates had no significant difference on age(P>0.05).3.On seasonal distribution,positive rate of other viral detection of case patients was higher than control subjects among all seasonals(P=0.000).viral detection of case patients has obvious seasonal distribution and mainly detected in winter and spring.The 11 kinds of respiratory viral of case patients,IFV-B、IFV-C and PIV4 have no obvious seasonal distribution, RSV mainly detected in late winter and early spring,HMPV,ADV,HBo V,IFV-A and PIV1-2 show a peak in the spring,summer,summer,winter,autumn.The detection rates of control subjects had no significant difference on seasonal(P=0.860).4.In cases,the co-infection rate was 44.38%.The 11 kinds of respiratory viral,PIV4 and IFV-C mainly co-infection,in contast,IFV-B mainly single infection. The mean viral load of RSV was highest,followed by HMPV、HBo V、PIV I-IV、ADV was lowest.Besides RSV,the mean viral load had no significant difference between case patients and control subjects among the 11 kinds of viral(P>0.05).PIV2 loads were lower in viral co-infection compared to single infection,IFV-C,in contrast to PIV2.The mean viral load of RSV、ADV、HBo V、HMPV、IFV-A、IFV-B、PIV1、PIV3 had no significant difference between single infection and co-infection.5.The viral detection rate of lower respiratory tract infection(LRTI) was higher than upper respiratory(URTI),the detection rate of LRTI disease has no statistical difference.Only detected RSV、PIV2 and PIV3 in the URTI,and URTI main is pneumonia,The main viral pathogenies of bronchiolitis,pneumonia and severe pneumonia was RSV.The viral loads was higher in children with bronchiolitis than children with bronchitic and pneumonia in IFV-A,viral loads of other viral had no significant difference between URTI group and LRTI group.6.AS detecting RSV viral load was 104.17copies/ml,the relationship between RSV infection and clinical symptons diagnostic specificity,when the viral load was lower than 102.02copies/ml,it may has nothing to do with the cinical symptoms of viral load.7.The mainly detection type of ADV and HMPV was type B(ADV-3) and A2 b,respectively.