Rotavirus Department, National Institute of Virology, 20-A, Dr. Ambedkar road, Pune-411 001, India.
Abstracts of the papers presented at the XVIII National Conference of Indian Virological Society at Post Graduate Institute of Medical Education and Research, Chandigarh, India, December 11–13, 2008.
Knowledge about molecular epidemiology of Norovirus (NoV) infections in India is limited. The present study was designed to understand the molecular epidemiology and genetic diversity of norovirus infections in Pune, western India. A total of 570 fecal specimens collected during July 2005–June 2007 from 520 hospitalized and 50 OPD children (d” 5 years) with AGE were tested for the presence of NoV Genogroup (G) I and GII by RT-PCR using primers targeting RdRp gene followed by genotyping of positive specimens with primers specific for VP1 gene. Sequencing and phylogenetic analysis were carried out to identify circulating genotypes. NoV infections were detected in 72/570 (12.6%) specimens with predominance of GII (97.2%). One (1.3%) specimen was positive for GI while one (1.3%) showed mixed infection with both GI and GII NoVs. The positivity rate up to the age of 2 years was significantly high [p<0.0001]. NoV activity peaked in March and persisted till June in both the years supporting summer month seasonality. The phylogenetic analysis of VP1 gene sequences identified 1 GI (GI. 2) and 8 GII (GII.4, GII.6, GII.7, GII.8, GII.12, GII.13, GII.14 and novel “GII.18”) genotypes. GII.4 (52%) prevailed in 2005–06 while novel genotype GII.18 contributed 36% of NoV infections. Interestingly, GII.3, not identified in 2005–06, predominated (50%) in 2006–07 while genotype GII.18 disappeared completely. The results highlight distinct epidemiological and molecular features of NoVs circulating in Pune, western India and emphasize the need for surveillance studies in other regions of India.
