[Molecular epidemiological study on norovirus among children with acute diarrhea in Guangzhou].

ABSTRACT

OBJECTIVE: To study molecular epidemiology of norovirus (NV) infections, stool specimens collected from children with acute diarrhea were tested by TaqMan real-time reverse transcription polymerase chain reaction (RT-PCR) for the viral specific nucleic acid segments. METHODS: Fecal samples from a total of 1260 children who had watery diarrhea seen from December 2006 to December 2007 in Guangzhou were analyzed by real-time RT-PCR. The primers and probes used for rapid detection and typing of NV strain target NV sequences were at the ORF1-ORF2 junction, a highly conserved region of the NoV genome. The positive specimens were determined by nested PCR and sequenced. RESULTS: Totally 257 specimens were positive for NV with a positive rate of 20.40%. Shedding of NV type GI was detected in 6.90%, type GII in 16.98% respectively, while the positive number of mixed infection with GI and GII was 44. Of the NV strains that were cloned and sequenced, GI was GI-3, GI-2 and GI-4 detected in positive specimens respectively; meanwhile, GII-4 was most commonly seen in genome II, followed by GII-3 and GII-7. In addition, the average age of children infected with NV was less than 2 years. An epidemic occurred during the winter and early spring (December through the next March). CONCLUSION: NV was one of the important pathogens for acute diarrhea among children in Guangzhou, which suggested GII-4 was the prevalent strain.