Identification of Thai C-18 Virus as a Member of the Coackie Virus A20 Subgroup,∗

Summary Thai C-18 virus, previously believed to be a new enterovirus type, has been shown to belong to the Coackie virus A20 subgroup. Four antigenic variants are now known for this subgroup. The indicator strain of choice within the subgroup is A20A, as it is most readily neutralized by antisera against all 4 variants.