Molecular And Epidemiological Study Viral Diarrhea On Among Children Under5Years Old In Nanjing

Part1:Molecular and Epidemiological Study on Common Diarrheal Viruses among children under5years old in NanjingObjective:To give a systemic picture of the molecular epidemiology of diarrhea viruses among children under5years, a case-control study was carried out in Nanjing from2010to2011,which can provide the evidence for the prevention and treatment of children with viral diarrhea.Methods:The stool specimens and clinical data were collected from428children with acute diarrhea and428healthy children in Nanjing Children’s Hospital of Nan jing Medical University from July2010to June2011. Human rotavirus was detected using ELISA kit and typed by nested RT-PCR.human calicivirus and human astrovirus were done by reverse transcription polymerase chain reaction (RT-PCR)while polymerase chain reaction(PCR) was employed to detect Human adenovirus.Results:1. At least one of the four viral agents was found in57.0%(244/428)of the specimens. Human rotavirus,human calicivirus,human astrovirus and human adenovirus were identified in43.9%(188/428),14.7%(63/428),3.97%(15/428) and3.03%(13/428)respectively.Rotavirus G1(39.9%) was the most prevailing serotype followed by G3(22.3%).Within the P genetype P [8](68.1%) was the most common genotype. The most common G-P combination was G1P[8](31.4%).58(92.1%)out of63HuCVwere norovirus GⅡ and5were sapovirus,while GⅡ-42006b was the predominant strain Among15astrovirus strains, serotype1was the predominant, Serotype5was found only in one case.Adenovirus belonged to three subgenera (A, B and C) with three serotypes(AdV1, AdV31and AdV41), within these serotypes, AdV41was the most prevaling serotype.2. In the428control samples,9.11%were positive for the common diarrheal viruses.3 Rotavirus were detected.19samples were positive for calicivirus, there were8NoV and13SaV(Including3co-infection cases). The positive rate of HAstV was3.03%. Among which10samples were AstV5, there were two AstVland one AstV6. Each of AdVl, AdV3and AdV12was one sample.35of428(8.18%) samples were found positive with two viral agents, the rate of HRV coinfections with other viruses is91.4%(32/35).In the control there were all mono infections,and a peak admission of viral diarrhea was observed from October to December.Conclusion:Viral diarrhea is the most common cause in infants and young children with acute diarrhea. Human rotavirus is the major pathogen contributing to the acute diarrhea.The predominant rotavirus strain circulated was G1P[8]. We should pay an attention to coinfection and asymptomatic infection. In addition to further understand ing diarrhea viruses epidemiology, long-term surveillance must be carried out. Part2. Relationship between human bocaviruses infection and acute gastroenteritis among infantsObjective:To explore the causative role of human bocavirus(HBoV)played in acute gastroenteritis in children, a case-control study was prospectively conducted to investigate HBoV detection in symptomatic children with acute gastroenteritis and asymptomatic children,to discuss the clinical characteristics of HBoV infection, the influence factors of HBoV detection and the differences between genotypes of HBoV.Methods:Between July2010and June2011,428stool specimens and clinical data were consecutively collected from children with acute gastroenteritis and428healthy children in Nanjing Children’s Hospital of Nanjing Medical University,During the same time,428stool samples were obtained from healthy children. HBoV was screened in all samples by real-time PCR method, and HBoV positive samples were typed by nested PCR.The nucleotide sequences were determined and analyzed by using MEGA5.0package, all statistical analyses were performed using SPSS17.0.Result:1.HBoV positive rate was22.9%(98/428) in428children with acute gastroenteritis and the average viral load was4.11×104copies/ml.While HBoV was found positive in38of428control samples. There was astatistically diffence in the detection rates of HBoV between the symptomatic group and the asymptomatic group(χ2=29.12, P=0.000).Co-infectin was more common in the case (χ2=31.47, P=0.000).2. In the case HBoV2detection rate was15.65%(66/428), there were36HBoV1and3HBoV3, no HBoV4detected; HBoV2detection rate and viral load were higher than HBoV1(P<0.02). HBoV2detection rate was highest6.07%(26/428) which was the highest detection rate in the control.HBoV1was detected in24(5.61%) cases, HBoV3and HBoV4were not detected. HBoV2detection rates and viral load was higher (P<0.05) in the case.3.About59.2%HBoVs were in the absence of enteric viruses (especially HRV), In41patients co-infected with HBoV2and HRV, More patients were noted with fever、vomiting than monoinfected crowd (P<0.02); there were only3mix-infection in the control. Multivariate conditional logistic regression analysis results showed that HBoV1was not associated with AGE, while the association between HBoV2and AGE was weaker ((OR=1.984, CI=1.052-3.742)) than that between AGE and HRV, HuCV and HAdV.HBoV2detection rates in the HRV group and the non-HRV group was statistically significant (χ2=13.92, P<0.05), single-factor conditional logistic regression analysis showed that HBoV2and HRV infection is relevant(OR=2.263, CI=1.446-3.541, P=0.000).Conclusion:1.Bocavirus infection is prevalent in the infant in Nanjing, the detection rate was next to HRV, logistic regression analysis shows HBoV2is a pathogen of infants and young children with acute gastroenteritis, but its role is weaker than HRV, HuCV and HAdV. Bocavirus infection does not affect the severity of the disease.2. Mixed infection is conmon, particularly mixed with HRV, patients co-infected with HBoV2and HRV is more prone to fever, vomiting.HRV may be a susceptible factors of HBoV infections.