| Part one:The viral spectrum investigation of hospitalized children with acute low respiratory tract infection in Changsha area from2010to2011Objective:To investigate the epidemic feature of common viral in Changsha area of hospitalized children with acute lower respiratory tract infection (ALRTI), provide baseline information for prevention and treatment of local children with acute lower respiratory tract infection.Method:1. Nasopharyngeal aspirates (NPAs) specimens from hospitalized children with acute lower respiratory tract infection at the pediatrics medical center of first affiliated hospital of Hunan normal university were Collected in Changsha from March2010to February2011.2. Polymerase Chain Reaction (PCR) was performed to detect adenovirus (ADV), RT-PCRs were applied to detect human parainfluenza virus type3(HPIV3), respiratory syncytial virus (RSV), human rhinovirus (HRV), type A and B of influenza virus (IFVA, IFVB), human metapneumovirus (HMPV), type NL63of human coronavirus (HCoV-NL63), type HKU1of human coronavirus (HCoV-HKU1), and Nest-PCRs were employed to detect human parainfluenza virus type1,2,4(HPIV1,2,4), and human bocavirus (HBoV). Then the amplicons were sequenced and subsequently subjected to the BLAST search against the non-redundant database of GenBank in National Centrer for Biotechnology.3. The epidemiological characteristics of various viruses in children with acute lower respiratory infections were analyzed.Results:1. Of all771NPAs specimens collected from Mar2010to Feb2011,536specimens contained viruses. The detection rate was69.52%(536/771). Of all the viruses detected, top three were HRV, RSV and HPIV3, followed by HBoV1, ADV, HMPV, HPIV4, IFVB, IFVA, HPIV1, HCoV-HKU1, HCoV-NL63, HPIV2and FBoV2.2. Of all536hospitalized children who were positive for virus detection,354were male (72.09%of the male hostipalized children), and182were female (65.00%of the female hospitalized children). The rate of positive detection rate between the male and the female is1.94:land statistically significant (X2=4.239, P=0.039), but there is no significant difference between the male and the female in terms of each virus.3. The ages of hospitalized children from whom samples were collected ranged from1day to14years, and the median age were23.65months.95.70%children infected with virus were under5years old, and 80.59%children were under3years old. The difference of virus detection rates among different age stages is statistically significant (X2=40.968, P=0.000). The RSV, IFVA, IFVB, HPIV3and ADV detection rate had significant difference in terms of age stages distribution, while the other virus detection rate had no significant difference.4. During the study period, discrepancy of seasonal distribution in whole year is statistically significant with regard to total virus detection rate (X2=22.211, P=0.000). The detection rate was most in spring. Seasonal distributions of different virus had different features. The summit of RSV detection rate arose in winter, and then spring. Both HRV and ADV had detection rate peaks in autumn, while most of HBoV1and HPIV3were detected in spring and summer, especially in summer. Many HPIV4were detected in summer, while the summit of IFVB and HMVP arose in spring. IFVA and HCo-HKUl could only be detected in summer and autumn.Conclusion:1. During the period of this study, the virus detection rate of hospitalized children with ALRTI reached up to69.52%, which indicated that virus made an important contribution to children with ALRTI in Changsha area.2. HRV, RSV and HPIV3occupied the top three in viral spectrum of hospitalized children with ALRTI. The ADV detection rate was higher obviously than former years.3. In this study, the virus detection rate of hospitalized children younger than3years old was80.59%. The discrepancy of virus detection rates among various age stages was statistically significant, and different viruses showed their own characteristics in terms of age stages distribution. The male had higher virus detection rate than the female, and the detection rate was most in spring. Seasonal distributions of different viruses had their respective features.Part two:The status quo analysis of HPIV1-4in hospitalized children with acute low respiratory tract infection in Changsha areaObjective:To investigate the epidemic characteristics of HPIV1-4in Changsha area of hospitalized children with acute lower respiratory tract infection (ALRTI). To investigate the epidemic status and clinical characteristic of HPIV4in local children with ALRTI and diversity between HPIV4and other viruses, lay the foundation for further study.Methods:1. NPAs specimens from hospitalized children with acute lower respiratory tract infection at the pediatrics medical center of first affiliated hospital of Hunan normal university in Changsha area from March2010 to February2011were collected.2. Nest PCRs were performed to detect HPIV1-4. Then the amplicons were sequenced and subsequently subjected to the BLAST search against the non-redundant database of GenBank in National Centrer for Biotechnology. MEGA4software was employed to analyze the outcome and draw cladogram.3. Analysis and comparison was done between HPIV4and other types of HPIV in children with acute lower respiratory infections in terms of the epidemiological and clinical characteristics.Results:1. Of all771NPAs specimens in this study,148specimens were detected to contain HPIV. The detection rate came up to19.19%(148/771). Subdividing HPIV to HPIV1, HPIV2, HPIV3and HPIV4, the number of samples positive for successive virus detection were12,4,107and28, the detection rates were1.55%,0.51%,13.87%and3.63%, respectively.2. When it came to the gender of hospitalized children from whom samples positive for HPIV werecollected,98children were male, and50children were female. The rate between the male and the female was1.96:1. The discrepancies of type1to4of HPIV positive rates between the male and the female were not statistically significant. All of hospitalized children positive for HPIV were below5years old, and majority of them were less than1year old. Furthermore, HPIV1was not detected in children below6months, and the positive rate in children between12months and36months was higher than other age groups. Only4cases aged between6months and36months were detected to be positive for HPIV2. Children who were younger than36months had the most HPIV3detection rate, and65.42%of positive cases were children below1year old. HPIV4were distributed evenly in children below5years old. Further statistical analysis showed that the discrepancy of HPIV detection rates among different age stages was not statistically significant except HPIV3(x2=29.648, P=0.000). The highest detection rate of both HPIV3and HPIV4arose in the summer. Of all samples positive for HPIV detection,88samples were not combined with any other viruses infections, while60samples were polyinfection (40.54%). Coinfection with HBoV were the most common. The coinfection numbers of type1to4of HPIV with other viruses were3,3,46and11, respectively.3. The detection rate of HPIV4ranked second among HPIV1-4. HPIV4a is the superior one among the two collaboratively prevalent sub-genes of HPIV4. The epidemics peak of HPIV4arose in the summer. HPIV4was detected in all age stages under5years old. The discrepancy of HPIV4detection rates is not statistically significant between the male and female. Clinical manifestations of HPIV4were similar with HPIV3. Conclusion:1. HPIV4infections presented in hospitalized children with ALRTI in Changsha area, and it made an important contribution.2. During the period of this study, HPIV4a was the superior one among the two collaboratively prevalent sub-genes of HPIV4. All of the hospitalized children positive for HPIV4were under5years old. The discrepancy of detection rates between the male and female was not statistically significant. The epidemics peaks of HPIV4arose in the summer. Clinical manifestations of HPIV4were similar with HPIV3.3. The epidemics of type1to3of HPIV in the period of this study had respective features. |
PDF Full Text Request