Molecular Epidemiologic Analysis of Group A Rotaviruses in Children with Diarrhea in Wuhan City, China, 2007

Abstract

Background: Rotaviruses are the major etiological cause of acute viral gastroenteritis in infants and young children worldwide, primarily in developing countries, producing a significant disease burden. Methods: To describe epidemiologic features and genetic characteristics of group A rotaviruses causing diarrhea in children and to estimate the relatedness or origin of the rotaviruses, a survey was conducted in Wuhan, China, 2007. A total of 889 stool specimens from diarrheal patients under 14 years old from Wuhan Children’s Hospital were analyzed. Many symptoms such as vomit, cough, fever, dehydration were marked. The positive rotavirus specimens was determined by PAGE and rapid immunochromatographic assay. Results: A total of 236 positive specimens performed further genetic analysis. Genotyping of rotavirus was determined by RT-PCR. By sequencing and phylogenetically assigning, two G9 strains were found out. In total, rotavirus detection rate of all stool specimens is 26.55% (236/889). By PAGE and rapid immunochromatographic assay, the detection coincidence rate was 86.42%. Unfortunately, the detection rate was independent of the symptoms. There were extremly significant differences of the detection rates in different age groups ( 2 = 33.53, P < 0.01). The detection rates in the winter season (42-64%), from October to December, were significantly higher than the other seasons(P < 0.05). Throughout the study period, P[8] was the most frequent P serotype (88.9%), and G3 was the most frequent G serotype (75.3%), and was mostly associated with VP4 genotype P[8](68.4%). And the G-type/P-type combination G3P[8] was the most common, followed by G1P[8], G2P[4] and G3P[6]. G1 +G3P[8], G3 +G9P[8], G2 +G3P[4] and other mixed G/P types were detected also. VP7 gene sequences of G9 rotaviruses were detected out by sequencing for two strains, showed extremely high sequence identities (99—100%) to each other and to a few G9 rotavirus strains reported in Asia. Conclusion: In our present study, the rotavirus-positive rate in children specimens was 26.55% in total. The monthly prevalence of rotavirus infection showed significant winter seasonality. It was evident that the G3P[8] rotaviruses were the most prevalent throughout the study period. These findings suggest that transmission of the G3 rotaviruses might have occurred endemically in Wuhan. The two G9 strains were phylogenetically assigned to lineage 3.