Etiological Study Of Enteric Viruses In Diarrhea Children Younger Than5Years Old In Chong Qing And Geneotype Analysis Of Norovirus, Sapovirus And Adenovirus

Objective:To determine the prevalence of rotavirus, norovirus, adenovirus, sapovirus and astrovirus in children less than5years old presented with diarrhea in Chongqing, China.Methods:Five hundred fecal samples, from August to November2010, were collected from children less than5years of age presented with acute diarrhea at the Children’s Hospital of Chongqing Medical University. All samples were tested for rotavirus A, B and C, norovirus GI and GII, adenovirus, sapovirus and astrovirus by ELISA, RT-PCR or PCR. Partial sequences of norovirus, sapovirus, adenovirus and astrovirus were phylogenetically analyzed to determine the genotypes.Results:A total of500fecal samples were collected from children younger than5years. The ratio between boys and girls was1.4:1. In all500cases,477cases are acute diarrhea and23cases are persistent diarrhea.One case with diarrhea lasted for two months. The samples from children with acute diarrhea,Rotavirus A was the most frequent virus identified in132cases (27.7%,132/477) and was followed by norovirus GII in130cases (27.3%,130/477), adenovirus in30cases (6.3%,30/477), sapovirus in9cases (1.9%,9/477) and astrovirus in1case (0.21%,1/477) respectively. In the23cases of persistent diarrhea, rotavirus A was detected in2cases, norovirus GII2cases, adenovirus1cases.For positive samples, partial sequences were sequenced and phylogenetically analyzed to determine the genotypes. Twenty-two of the norovirus GⅡ positive cases were selected randomly for genotyping, and GII/4(14/22,63.6%) was the predominant strain followed by GII/6(3/22,13.6%), GII/2(2/22,9.1%), GII/3(2/22,9.1%), GII/7(1/22,4.5%). Sapovirus was classified into4genotypes. GI/1was predominant and followed by GI/2, GII/1and GIV.For adenovirus, G41(17/31,54.8%) was the predominant strain. The mixed infections were found in25cases which all were cases with acute diarrhea. Group A rotavirus was the most common viral enteropathogen, which could be identified in132/477samples (27.7%). The ratio of the distribution of rotavirus infection between boys to girls was1.6:1which was not significant difference (P>0.05). More than96%of the detections occurred in children below the age of2years old. NoV GII was detected in130/477(27.3%) samples. The ratio of the distribution of NoV GII infection between boys to girls was1.5:1and there was not significantly difference (P>0.05). And More than93%of NoV GII-positive stool samples were from children<2years of age. Interestingly, no groups B, C rotavirus and norovirus group I were detected in this study.Conclusion:Enteric viruses are a major cause of diarrhea in children, younger than5years old, in Chongqing. Rotavirus A is the most common etiological agent and is immediately followed by norovirus. Adenovirus, sapovirus and astro virus also are the pathogens. For norovirus GII, sapovirus and adenovirus, the predominant strain are GII/4, GI/1and G41, respectively. Groups B, C rotavirus and norovirus group I are not the causes of diarrhea in children younger than5years old, in Chongqing..