Molecular characterization of calicivirus strains detected in outbreaks of gastroenteritis in Argentina.

Eight outbreaks of acute gastroenteritis occurred in Argentina in 2004 were tested for the presence of Calicivirus, Rotavirus and Astrovirus as possible causative agents. Caliciviruses were found in 39 out of the 100 tested samples, followed by six Astrovirus-positive samples and two Rotavirus-positive samples. Thirty-seven out of the 39 Calicivirus-positive samples were typed as Norovirus while the remaining two were typed as Sapovirus. Sequence and phylogenetic analyses of 13 Norovirus-positive samples revealed the presence of strains from the genogroups GI, GII, and GIV. Six Norovirus strains were grouped with the GIV-1 strains, three with the GIIb strains, two with the Farmington Hill-cluster (GII-4) strains, and the remaining two with the GI strains. To our knowledge, this study constitutes the first report of molecular epidemiology of human Caliciviruses associated to gastroenteritis outbreaks in Argentina and the circulation of GIIb and GIV-1 strains in South-America.