Genotypes of VP4 and VP7 of rotaviruses identified from infants and young children with diarrhea in Guangzhou City

Rotavirus is one of the most important pathogens causing diarrheal diseases in infants and young children worldwide VP4 and VP7 are the two major neutralization antigens of the virus, which induce the type specific protective antibodies against rotavirus infection Objective To understand the impact of rotavirus infection in infantile diarrhea and analyze the genotype distribution of rotaviruses in infants and young children with diarrhea in Guangzhou City Methods Stool specimens were collected from 1207 patients with non bacterial diarrhea who were hospitalized in Guangzhou Children′s Hospital from November 1994 to January 1998 Polyacrylamide gel electrophoresis (PAGE) were employed to detect rotavirus double stranded RNA (dsRNA) from stool specimens and cDNA fragments of the genes encoding VP4 and VP7 were amplified from the rotavirus RNA positive specimens by using RT PCR Genotypes of VP7s from the rotavirus positive specimens were determined by nested PCR and those of VP4 genes were determined by dot blot hybridization Results Rotavirus dsRNA was detected from 573 (47 5%) of 1 207 stool specimens Among them, 445 (77 7%) had long RNA electrophoresis pattern and 83 (14 5%) had short pattern, 15 (2 6%) had mixed RNA pattern,and 30 (5 2%) with very weak stain and were difficult to identify whether they belonged to long or short patterns Most of the rotavirus positive specimens (96 3%) were from those under 2 years of age, among them 49 6% were from patients 7 to 12 months of age The peak season for rotavirus infection in Guangzhou city was from November to February of the following year The most dominant G type of rotavirus in this group was G1 (86 0%) and P type was P1A (83 1%) G2 and G3 were the next important ones in this group Rotaviruses with G8 and G9 were also found in this study group Conclusion Rotavirus is one of the most important pathogens for diarrhea in infants and young children in Guangzhou City The most dominant genotype of rotaviruses circulating in Guangzhou was G1 P1A