Characterization of VP7 and VP4 genes of rotavirus strains: 1990-1994 and 2000-2002.

A total of 90 rotavirus-positive faecal specimens collected from patients hospitalized with diarrhoea in 1990-1994 (n=77) and 2000-2002 (n=13) were investigated for VP7 and VP4 genotypes. The specimens included 21 typable and 69 non-reactive or multireactive rotavirus strains as monitored by monoclonal antibody-based serotyping ELISA. Genotyping was carried out by multiplex PCR/sequencing using primers specific for both VP7 and VP4 genes. The contribution of common genotypes (G1P[8], G2P[4], G3P[8], G4P[8]) in causing rotavirus diarrhoea was 79.2% and 92.3% in the years 1990-1994 and 2000-2002, respectively, while G9P[8] infections were detected at lower levels (1.3% and 7.7%) at both time-points. There was a predominance of G1P[8] in 1990-1994 and of G2P[4] in 2000-2002. The detection of unusual rotavirus strains (G1P[6], G1P[4], G1P[19], G2P[8], G3P[4], G4P[6]) in 19.5% of the patients indicated a significant contribution of reassortants in causing diarrhoea in western India.