NCIt definition : A species of non-enveloped and spherical viruses with a capsid with T 3 icosahedral
symmetry in the Caliciviridae family and Norovirus genus. The genome is composed of
single-stranded, positive-sense RNA. Norwalk viruses are found in humans and causes
acute viral gastroenteritis. Norwalk viruses are transmitted via oral ingestion or
fecal-oral contamination.;
Alternative definition : CDISC: Any viral organism that can be assigned to the species Norwalk virus.;