Molecular Epidemiologic Characterization And Clinical Related Data Analysis Of Rotavirus In Infants Of Chongqing

Objective:This study is to investigate the rotavirus epidemiological data, analyse the prevalence, and acquire the molecular epidemiological features of rotavirus in Chongqing infants and young children. It is very important for the development and introduction of rotavirus vaccine which suit for Chongqing infants and young children, providing an objective basis for establishing accure health policy to prevent local rotavirus enteritis.In addition, this study can also contribute to distinguish whether there are significant differences in rotavirus enteritis clinical features among each major types or combinations. It is important for reseaching the clinical characteristics of rotavirus enteritis furtherly. And it has great values in judging whether focus on some certain types of rotavirus in the prevention and treatment.Methods:1. Specimens and clinical data collectionAll the stool specimens of children aged 1 month -14 who visted Chongqing Medical University Children's Hospital due to acute non-invasive diarrhea during August 2008 ~ July 2009 period (12 months) had been collected.Date of the patients include total number, date of attendance, name, sex, age, contact details, time of onset, sampling time, clinical symptoms, prognosis, stool microscopy results, history of suspected contaminated food exposure and diarrhea patients exposure.2. Laboratory specimen processingFecal specimens and questionnaires were collected from infants with non—bacterial acute diarrhea who were seen at Children Hospital Of Chongqing Medical University from October,2008 to Februery,2009. Nested RT-PCR(nested reverse transcription polymerase chain reaction) method was used for rotavirus-positive specimens which been tested by screening method with colloidal gold and proved by RT-PCR method to genotype VP7 and VP4 gene(G- and P- typing).Statistical analysisSPSS16.0 was used to analyze the clinical data and experimental data. To compare the median non-parametric use Mann-Whitney U test, a number of independent samples of non-normal distribution use Kruskal-Wallis test, and to compare the rate use chi-square test.Statistical significance was assumed for P < 0.05.Results:453 samples (out-patient 359 cases, patient 94; male 266 cases, female 187) are positive cases by rotavirus screening among the 1259 samples collected throughout the year (out-patient 1054 cases, patient 205; male 767 cases, female 492). Rotavirus positive rate was 35.98% overall (453/1259), of which 34.06 percent out-patient (359/1054), hospitalization 45.85% (94/205); male infection rate 34.68% (266/767), female-positive rate of 38.01% (187/492). The data shows that children with rotavirus enteritis mainly occurred in 6 months to 14 months. Rotavirus enteritis occurs throughout the year in Chongqing, but mainly in October to next February, and in March to April shows a small peak and July to September low.To analysis of rotavirus epidemiology in epidemic seasons (October to next February), a total of 507 infants stool specimens were collected. Rotavirus antigen positive rate is 50.69% (257/507). 147 cases of the rotavirus-positive specimens were selected to genotype. The G-genotype resusts shows that G1-type accounts for 40.14% (59/147), G2 6.80% (10/147), G3 17.01% (25/147), G4 2.04% (3/147), G9 0.68% (1/147), respectively. While 49 cases (33.33%) were failed to detect G-genotypes. Corresponding, P [8] type accounted for 60.54% (89/147), P [4] 6.12% (9 / 147), P [9] and P [10] each of 0.68 % (1/147), respectively, and 47 cases of failed P-genotyping.Conclusion:1. The study indicates that children with rotavirus enteritis mainly occurred in the 6 months to 14 months aged infants. There is no statistical difference between male and female in the incidence of children with rotavirus enteritis throughout the year. Rotavirus enteritis occurs throughout the year in Chongqing, but mainly in October to next February, and in March to April shows a small peak.2. Infants with rotavirus enteritis usually have two prominent symptoms - fever and vomiting - which are different from other enteritis.3. The diversity feature is showed in Chongqing rotavirus G-genotypes, but P [8] type is still dominant in P-genotypes. Rotavirus enteritis has the same clinical manifestations among all the serotypes and combinations. Preventions and treatments of those are all needed.