A Study On Viral Etiology Of Children With Acute Lower Respiratory Tract Infection In Lanzhou From2011to2012

ObjectiveTo study the etiology and epidemiology characteristics of14related viruses of acute lower respiratory tract infection(ALRTI) in children in Lanzhou area from December2011to November2012. To provide reference for clinical diagnosis,disease prevention and control.Materials and methods1.Collected387nasopharyngeal aspirates(NPAs) from children with acute lower respiratory tract infection in the First Hospital of Lanzhou University from December2011to November2012.We added2ml virus preservation solution to NPA and stored at-80℃.All specimens were collected since the child admitted to hospital the same day or within three days, the process obtained families informed consent.2.We used Real-time PCR method to detecte RSV, HRV, ADV, PIV1-4, HMPV, HBoV, IFVA, IFVB, HEV, HKU1, NL63.3.We Used Nested-PCR to detecte ADV-positive specimens, The HRV-positive and HEV-positive specimens were detected by reverse transcriptase PCR(RT-PCR), the final products were sequenced-based typing. Results1.In all387specimens, there were366specimens were detected at least one kind of virus,the total virus detection rate was94.57%, the detection rates from high to low in turn was RSV52.97%, HRV24.55%, ADV16.80%, PIV314.47%, HMPV12.14%, HBoV10.08%, NL638.27%, IFVA4.65%, IFVB4.65%, PIV43.36%, PIV12.84%, HEV2.58%, PIV21.55%, HKU10.26%.2. In this study, the virus total detection rate was significantly higher in less than3years old children than in children over3years old. The RSV detection rate was highest in children less than6monthes, HMPV and IFVA detection rate were highest among3years to5years, IFVB detection rate was highest among6monthes to1year old, PIV3detection rate was significantly higher in less than3years old, other7viruses detection rates had no significant difference on age.3. The virus total detection rates had no significant difference on gender and season. In the14kinds of viruses, ADV, IFVA, IFVB were highest in spring; NL63was highest in summer; HRV and PIV3were highest in autumn; RSV and PIV1were highest in winter, HEV was higher in autumn and winter, there were no significant difference on season about HMPV, HBoV, PIV4, PIV2and HKU1.4.In this study, the prevalence rates of bronchiolitis between boys and girls were44.27%(116/262) and35.20%(44/125), the prevalence rate of bronchiolitis had no significant difference on gender. The mean age of children with bronchiolitis was younger than children with no-bronchiolitis LRTI, it had significant difference on age. In this study,the main viral pathogenies of bronchitis were HRV、ADV and PIV3; The main viral pathogenies of pneumonia were RSV、HRV and ADV; The main viral pathogenies of bronchiolitis were RSV、HRV and ADV.5.In this study, the co-infection rate was50.55%(185/366), NL63, HBoV and ADV had the highest co-infection rate. RSV, HBoV and HEV loads were lower in viral co-infection compared to single infection. The detection rate was higher in children with bronchiolitis than children with bronchitic and pneumonia, the viral loads of RSV and HBoV were higher in children with bronchiolitis.6.0f the95HRV-positive specimens, there were45specimens could be typed. HRV-A (28cases)was the dominant type of HRV in Lanzhou area, followed by HRV-C(16cases) and HRV-B(1case). The mean viral load of HRV-C was higher than HRV-A, the mean age between HRV-A and HRV-C had no significant difference. Of the65ADV-positive specimens, there were44specimens could be typed, the results indicated that there were20cases in subgroup B(ADV-37cases, ADV-79cases, ADV-144cases),10cases in subgroup C(ADV-14cases, ADV-212cases, ADV-53cases) and5cases in subgroup F(ADV-413cases, ADV-402cases), There was no subgroup A, D E and G in this study. Conclution1. Virus played an important role in children with acute low respiratory tract infection, the most common three were RSV, HRV and ADV. HCoV-NL63detection rate was significant higher than before in Lanzhou area, there need further continuous monitoring and attention. 2.Children with bronchiolitis had a higher virual detection rate, this indicated that the occurrence of bronchiolitis associated with viral infection.3. The viral loads of RSV and HBoV were higher in children with bronchiolitis, this indicate that high viral load of these two viruses associated with wheezing.