Norovirus and sapovirus infections in Thailand.

Stool specimens collected between November 2002 and April 2003 from hospitalized infants with acute gastroenteritis from four distinct geographical regions in Thailand were examined for norovirus (NoV) and sapovirus (SaV) by reverse transcription-PCR and sequence analysis. Of the 80 specimens examined, we identified 11 NoV and 9 SaV single infections, and 3 NoV/SaV mixed infections. The majority of NoV strains (64%) belonged to genogroup II/ genotype 4 (GII/4; Lordsdale cluster). Other NoV strains co-circulating belonged to GII/1, GII/3, GII/6, and one new genotype cluster (GII/New). The majority of SaV strains (83%) were from the Manchester cluster. One isolated SaV strain represented a recently discovered novel genogroup within the SaV genus (SG-V), and another isolated SaV strain represented a novel SaV genogroup II cluster.