A survey of FMD type 'O' strains from the Far East

A survey of 'O' strains submitted from Far Eastern countries has been conducted, comparing the strains with standard reference strains and with each other. The results indicate differences between these strains but they cannot be arranged in clearly distinct groups. There is, rather, a continuous variation with cross-relation between strains occurring more or less haphazardly. This makes the subgrouping of a large number of strains extremely difficult and supports the view expressed in other papers in this symposium that current concepts of subtyping should be revised to take into account multiple antigenic relationships.