ABSTRACT
The classification scheme was based on an electron microscopical study which was carried out on many but not all of the small round viruses described in the literature. The ability to propagate serially at least some human astroviruses will facilitate the biochemical characterization of the Oxford group of uniquely structured small round viruses and will confirm their ribonucleic acid (RNA) genome and polypeptide composition, thus allowing a more definitive taxonomic status. A further small round virus was reported by Japanese workers as a consequence of a study of nonbacterial gastroenteritis which occurred in an orphanage in Sapporo. The first report of "featureless" small round viruses in human feces relates to the studies carried out on an outbreak of winter vomiting disease which occurred in a boy's boarding school in England. The most extensively studied human fecal candidate parvoviruses are the Wollan, Ditchling, Cockle, and Parra-matta agents.
