Rotavirus And Astrovirus Infection And The Typing Characteritics Among Children Under 5 Years Old

Objective:The technology of RT-PCR combined with cell culture was used to study the prevalence and genotypes of rotavirus(RV) and human astrovirus(HAstV) among children under 5 years old hospitalized with viral diarrhea in Tianjin.Methods:Stool specimens were collected from hospitalized diarrhea children in Tianjin children's hospital between May 2008 and April 2009. Detection of rotavirus and astrovirus was employed by Colloidal Gold Device and enzyme-linked immunosor bent Assay (ELISA). The detected postives were inoculated to MA-104 cells and CaCo-2 cells. The total RNA of virus was extracted after CPE which was caused by rotavirus and astrovirus were observed. The genetic identities of the strains were determined by using RT-PCR and sequencing the RT-PCR products. The sequence results were analysed by DNASTAR and BLAST. The clinical data also were collected.Results:Rotavirus antigen was found positive in 28.39% of the patients (245/863). Among all the children with rotavirus diarrhea,89.39% were<24 months. The prevalence of rotavirus diarrhea in children peaked during Oct,2008 through Apr,2009. Male to female is 2.10 to 1. Main symptoms included diarrhea, fever, vomiting and accompanied with different extent of dehydration. Of the 208 rotavirus positive specimens,95 were successfully identified by RT-PCR. Thirty-five positive strains of RV were sequenced, and the sequencing results showed that 32 positive strains were belonged to rotavirus G1 type,2 positive strains were belonged to rotavirus G3 type andl positive strains were belonged to rotavirus G9 type.Astrovirus antigen was found positive in 2.99% of the patients (25/863),6 were coinfected with rotavirus, and the coinfection rate was 24.00%(6/25). Among all the children with astrovirus diarrhea,96.00% were <24 months,44.00% were<6 months. The prevalence of astrovirus diarrhea in children peaked during Oct,2008 through Apr,2009. Male to female is 1.74 to 1. Main symptoms included diarrhea, fever, vomiting, only one sample was accompanied with light dehydration. Of the 21 rotavirus positive specimens,11 were successfully identified by RT-PCR and they were all serotype 1.Conclusion: RV was the dominance etiological agent for infantile diarrhea in Tianjin, and the predominant serotype was G1. Astrovirus was a major cause of nonbacterical diarrhea between 2008 and 2009 in Tianjin, and the predominant serotype was typel.