RESUMO
Noroviruses are the leading cause of acute gastroenteritis (AGE) in all age groups worldwide. Despite the high genetic diversity of noroviruses, most AGE outbreaks are caused by a single norovirus genotype: GII.4. Since 1995, several different variants of norovirus GII.4 have been associated with pandemics, with each variant circulating for 3 to 8 years. The Sydney_2012 variant was first reported in Australia and then in other countries. A new variant, GII.P16-GII.4, was recently described in Japan and South Korea and then in the USA, France, Germany and England. In our study, 190 faecal specimens were collected from children admitted to a paediatric hospital and a public health facility during a surveillance study of sporadic cases of AGE conducted between January 2015 and July 2016. The norovirus was detected by RT-qPCR in 51 samples (26.8%), and in 37 of them (72.5%), the ORF1-2 junction was successfully sequenced. The new recombinant GII.P16-GII.4 Sydney was revealed for the first time in Brazil in 2016 and predominated among other strains (9 GII.Pe-GII.4, 3 GII.P17-GII.17, 1 GII.Pg-GII.1, 1 GII.P16-GII.3 and 1 GII.PNA-GII.4). The epidemiological significance of this new recombinant is still unknown, but continuous surveillance studies may evaluate its impact on the population, its potential to replace the first recombinant GII.Pe-GII.4 Sydney 2012 variant, and the emergence of new recombinant forms of GII.P16.
