serological and genomic characterization of l338 a novel equine group a rotavirus g serotype a group a rotavirus designated l338 was isolated from the faeces of a diarrhoeic foal and was compared to 11 standard g serotype strains of group a rotaviruses by crossneutralization it was clearly distinct from serotypes g1 to g11 and thus representative of a novel rotavirus g serotype tentatively designated g13 the nucleic acid sequence of the virion protein 7 vp7 coding region was determined and the deduced amino acid sequence compared to published sequences within vp7 regions a and b l338 was clearly distinct from serotypes g1 to g12 excluding g7 which has not been sequenced but region c was very similar to those of g3 and g8 this further questions the significance of region c in determining serotype specificity of at least three distinct rotavirus g serotypes