MULTIPLE-INFECTED DIAGNOSTIC SPECIMENS FROM FOOT-AND-MOUTH-DISEASE ENDEMIC REGIONS

The current routine diagnostic procedures for foot and mouth disease ( FMD) virus antigen detection combine the use of an indirect sandwich e nzyme-linked immunosorbent assay (ELISA) with virus isolation and ampl ification on cell culture. Several field samples recently received by the World Reference Laboratory for Foot and Mouth Disease which were i nitially diagnosed as containing a single virus type have subsequently been found to contain an additional virus type. Examples are given of the results of ELISAs performed on certain Saudia Arabian samples; th ese examples illustrate the problem which such multiple-infected sampl es present for laboratory diagnosis.