Pathogenesis of foot-and-mouth disease in swine, studied by in-situ hybridization.

Eight 7-month-old pigs were inoculated intradermally with 10(3) plaque-forming units of foot-and-mouth disease virus, type O, and killed 24, 48, 72, or 96 h later. Numerous tissues from each animal were collected and examined histopathologically and by in-situ hybridization to determine the presence of virus and its correlation with lesion development. The probe for in-situ hybridization was a biotinylated 500-base negative-sense transcription product corresponding to a portion of the gene encoding polymerase. With this technique, virus was shown to be widely disseminated in all epidermal tissues, regardless of histologically apparent cellular disruption.