Norovirus genotype IIb associated acute gastroenteritis in India

Background: In India the role of noroviruses in causing gastroenteritis is not well defined. Objective: To determine the norovirus prevalence in sporadic cases of acute gastroenteritis in western India. Study design: A total of 236 fecal specimens consisting 192 specimens from hospitalized and 44 from OPD (outpatient department) children <= 5 years of age were tested for the presence of norovirus genogroup (G)l and GII by RT-PCR followed by sequencing. Multiple alignment and phylogenetic analysis were carried out to determine the norovirus genetic types. Results: Norovirus GII infection was detected in 11.9% (28/236) specimens. These included 24 of 192 (12.5%) specimens from hospitalized and 4 of 44 (9.0%) specimens from OPD cases. Nucleotide sequence based analysis of norovirus GII strains indicated circulation of GIIb strains at a significant level in hospitalized (12.5%) and OPD (75%) children. Conclusion: This study demonstrates the predominance of GII/4 (genogroup II/genotype 4) along with co-circulation of GII/1, GII/2 GII/3 and Glib revealing the possibility of norovirus as the second most common cause of non-bacterial acute gastroenteritis after rotavirus in western India. It also documents for the first time occurrence of norovirus Glib infections in India. (C) 2008 Elsevier B.V. All rights reserved.