Epidemiological characteristics of rotavirus caused diarrhea in children aged 5 years in 26 provinces in China, 2011-2014

Objective To investigate the epidemiological characteristics of rotavirus caused diarrhea in children aged 5 years in China. Methods Diarrhea surveillance was conducted in emergency or outpatient departments of 162 hospitals in 26 provinces of China, the clinical and epidemiological data of the diarrhea cases collected and fecal specimens collected from the cases were sent to 92 network laboratories for detection of rotavirus by enzyme linked immunosorbent assay (ELISA), reverse transcription PCR (RT-PCR) and nested PCR, etc. The detection rate of rotavirus in different areas, population and times as well as its gene mutation during 2011-2014 were analyzed. Results Among 19849 diarrheal cases surveyed, 22.9% were infected with rotavirus. The positive rate in age group 12-24 months was highest (29.0%), followed by age group 6-12 months (26.1%). The detection rate was highest in watery stool samples (26.2%). The detection rate of rotavirus was highest in winter (39.4%) and lowest in summer (9.9%) in a year. The detection rate was higher in southern China (28.0%) and central China (27.0%) than in other areas. The most prevalent genogroup of rotavirus detected was group A, accounting for 95.1%.Among rotavirus group A, G9 P8(39.5%), G1 P8(16.8%) and G3 P8(9.9%) were the most common genotype, and G9 P8 had become the most common type of rotavirus group A gradually in China instead of G1 P8 and G3 P8. Conclusion Rotavirus was the major pathogen causing diarrhea in children aged5 years in China. The positive detection of rotavirus showed obvious spatial-temporal pattern. G9 P8 was the most common genotypes of rotavirus group A.