The Molecular Epidemiology Of Rotavirus Enteritis Among Children Under 5 Years

Objectives:This study aimed to evaluate the prevalence of rotavirus and to summarize the clinical characteristic of rotavirus enteritis and to investigate the genotypes of rotavirus strains causing acute gastroenteritis among children aged<5 years old in Chongqing. Then to evaluate the value of rotavirus vaccination used in Chongqing and provide reference information for the establishment of control strategy.Methods:Outpatients aged under 5 years old with acute uninvasive gastroenteritis treated in children's hospital of Chongqing medical university were enrolled during Jan.2014 to Dec.2014. The fresh stool samples were detected with enzyme immunoassays (EIA) for group A rotaviruses. Rotavirus-positive specimens were genotyped by nested RT-PCR.Results:1) A total of 495 stool samples were collected, RV was confirmed in 188 out of 495 (37.98%), and 111 cases were male and 77 cases were female. The constituent ratio were 59.04% and 41.96%, positive rate were 40.07% and 35.32% respectively. There was no significant difference in the gender distribution (?2= 1.169, P=0.28). Among the 495 patients, there were 86 cases in<6 months group,187 cases in 6-12 months group,163 cases in 13-24 months group,38 cases in 25-36 months group,14 cases in 37-48 months group,7 cases in 49-60 months group. Positive rate of various age groups were 20.93%,33.16%,50.92%,47.37% ,50.92% and 28.57%, respectively. Rotavirus was found through the whole year,the winter and autumn seasons were significantly associated with rotavirus infection, positive rate of the four seasons were 19.12%,8.70%,32.37% and 19.12% respectively.The positive rate in Nov.(52.56%),Dec.(70.15%) and Jan.(52.99%) were significantly higher than other months.2) Clinical manifestations of rotavirus enteritis:it was always accompanied by vomiting, fever and respiratory symptoms. And vomiting is the most common associated symptoms (117/176,66.48%). The fever accompanied with rotavirus enteritis was mild or middle, and rotavirus enteritis was more often accompanied by fever than norovirus enteritis, and the degree of fever accompanied with rotavirus enteritis was higher than that accompanied with norovirus enteritis (?2=5.69, P=0.017). There were 22/176 (12.50%) of rotavirus enteritis patients has history of using antibiotics for diarrhea before come to a doctor.3) Genotyping:G and P genotypes of rotavirus were detected in 143 out of 188 rotavirus positive specimens confirmed by the colloidal gold method with RT-PCR assay (76.06%). G9 (66.43%) was the predominant G-type, followed by the G1(11.19%), G2(5.59%) and G3(9.79%), respectively. And there was 10 samples (7.00%) were untyped. P[8] (88.81%) was the predominant P-type, followed by P[4] (6.29%),7 samples were untyped. The G/P combination genotype were G9P [8] (62.24%), G1P [8] (10.49%), G3P [8] (9.79%), G2P [4] (4.90%), G2P [8] (0.70%) and G9P [4] (0.70%). And there were 16 cases un-typed(11.19%) by G/P genetyping.Conclusion:Rotavirus is the main pathogen that cause acute diarrhea among children under five years old, children of 6m-3y are particularly susceptible. The incidence of rotavirus enteritis among male and female was no significant difference. Rotavirus was found through the whole year but winter and autumn seasons were significantly associated with rotavirus infection in Chongqing.Rotavirus enteritis always accompanied with vomiting, fever and respiratory symptoms.Vomiting is the main accompanying symptoms of rotavirus enteritis, rarely only accompanied with fever or respiratory symptoms. The fever accompanied with rotavirus enteritis always is mild or middle, and respiratory symptoms are mild. There is no significant difference between rotavirus enteritis and norovirus enteritis in the degree of fever. There is no need to use antibiotics for the treatment of rotavirus enteritis, but there was unreasonable use of antibiotics. The epidemiology of G type presents the diverse and changeful tendency in Chongqing.The research shows that G9 is the advantage popular G serotype, Combination serotype G9P[8] was the advantage genotyped in Chongqing region, followed by G1P [8], G3P [8]. The molecular epidemiology of rotavirus is complex and changeful in Chongqing. This study provide some information for developing and bring in rotavirus vaccines to chongqing.