The pathology of a spontaneous and experimental mucosal disease-like syndrome in sheep recovered from clinical border disease.

The pathological changes which accompanied a severe clinical syndrome characterized by intractable diarrhoea and/or respiratory distress in sheep recovered from clinical Border disease consisted of inflammatory lymphoproliferative lesions in several organs, notably the CNS and intestinal tract. The syndrome has been reproduced experimentally by "super-infection" with homologous Border disease virus. The differential diagnosis is discussed and attention drawn to the similarity between the enteric lesions and those of bovine mucosal disease.