Pigs that had died after vaccination with a lapinized K strain of the swine fever virus at the persistence of another infection showed morphologic and histopathologic changes that were largely similar to those observed in cases of classic hog cholera. The difference consisted in the frequence and intensity of the lesions. Histopathologically essential proved the investigation of the brain. The latter usually presents a prevailing activation and hyperplasia of the capilary endothelium, while in classic swine fever there are lesions chiefly observed in the mesenchymal tissue with the formation of perivascular lymphoid-cell prolierations.