Molecular characterization of group A human rotaviruses in Bangkok and Buriram, Thailand during 2004-2006 reveals the predominance of G1P[8], G9P[8] and a rare G3P[19] strain.

The aim of this study has been to determine the incidence of diverse human rotavirus strains circulating in Thailand between October 2004 and April 2006 by means of molecular characterization. Pediatric patients aged between 2 months and 5 years diagnosed with acute diarrhea (n=307) in Bangkok and Buriram, Thailand were tested for human rotavirus A (RV-A) by RT-PCR. A total of 130 specimens (42.3%) were found RV-A positive and 126 were characterized by direct sequencing of the capsid glycoproteins VP7 and VP4. BLAST/FASTA analysis and phylogenetic analysis revealed genotypes G1P[8] (85.7%), G2P[4] (2.4%), G2P[8] (0.8%), G3P[8] (1.6%), G9P[8] (8.7%), and the uncommon strain G3P[19] (0.8%). Varying sites of polymorphism over time imply dependence on geographical location along with seasonal variation of relative incidence and distribution of rotavirus types. Thus, continuous molecular monitoring of human rotavirus epidemiology is essential for adjusting vaccine development.