Molecular Epidemiology Of Rotavirus Among Children Under 5 Years Old Hospitalized For Diarrhea In Three Areas Of China

Background:Group A rotavirus is the most common cause of severe diarrhea among infants and young children worldwide.An estimated 600,000 children die from rotavirus diarrhea each year,with 80%of these deaths occurring in developing countries.Now it has no specific remedy for rotavirus diarrhea and further improvement in hygiene is unlikely to prevent the disease.The development and introduction of rotavirus vaccines for children has been given high priority by the World Health Organization.In order to develop and implement RV vaccine for children under the age of 5 years in China,it is very important to understand the epidemiological characteristics of rotavirus.Objectives:1.Determine the epidemiological characteristics of rotavirus diarrhea in children aged＜5 years in China cities and countryside and provide suggestions for prevention and control efforts of RV diarrhea.2.Conduct a molecular epidemiological study of rotavirus stains to provide basic information for the development of RV vaccine.Methods:Stool specimens and individual cases information were collected from children less than 5 years of age who were hospitalized of acute gastroenteritis at 25 different hospitals in three areas of China,between October 2007 and September 2008. Dako IDEIA^TM kit was used for detection of rotavirus and reverse transcription-polymerase chain reaction(RT-PCR) was performed for determination of G serotype and P genotype of the rotavirus.Results:Stool samples from Gansu,Jiangsu and Jilin Provinces were analyzed for RV to determine by ELISA and the positive rate was 30.83%,26.24%,40.94%, respectively.The rate of the age for the children who were younger than 2 years old from these 3 areas was 96.18%,95.33%,94.19%,respectively.From October 2007 to January 2008,RV prevalence of children from Gansu was 56.91%,from Jiangsu was 45.58%,and from Jilin was 60.64%.RV prevalence peaked from October 2007 to January 2008.In total,the RV positive rate of hospitalization among children in city was 39.25%,in countryside was 29.68%.And 38.44%of hospitalized boys in city were RV positive,while 30.31%in countryside were RV positive;40.65%of hospitalized girls in city were RV positive,while 28.67%in countryside were RV positive.In city,RV positive children who were＜2 years old occupied 96.67%,while in countryside was 94.12%.In prevalent season,53.89%hospitalized children in city were positive for RV,while 56.77%in countryside;In non-prevalent season,26.69% hospitalized children in city were RV positive,and in countryside is 16.02%.The most prevalent single G type detected between October 2007 and September 2008 in Jilin Province was the G3(69.29%) and was followed by G1(7.88%).The P type distribution in specimens collected in Jilin Province showed predominately P[8] (68.46%)as the most common P type,followed by P[4](3.87%).The predominant G-P combination was G3P[8](78.46%),followed by G1P[8](6.72%),G3P-MX (4.15%),G-MX P[8](2.57%).Ten other combinations were also identified.Conclusions:Rotavirus remains the most significant viral agent causing diarrhea hospitalization among children under the age of 5 years in China.The most common children with rotavirus infections were younger than 2 years old.RV prevalence peaked from October to January next year.RV prevalence of children in city is higher than in countryside.The predominant strains of rotavirus were G3 and P[8]in Jilin Province.Information on the diversity and complexity of RV strains circulating in three areas of China provides useful data for formulating vaccine policy and evaluating vaccine efficacy.