3Cheville NF, Mengeling WL. The pathogensis of chronic hog cholera ( swine fever) : Histologic, immunofluorescent, and electron microscopic studies [ J]. Laboratory Invest, 1969, 20 : 261 - 274.
4van der Molen EJ, van Oirschot JT. Congenital persistent swine fever (hog cholera) I . Pathomorphological lesions in lymphoid tissues, kidney and adrenal[J]. Zentralblatt für Veterinaermed( B),1981, 28: 89-101.
5van Oirschot JT. Persistent and inapparent infections with swine fever of low virulence: Their effects on the immune system [ C ].State univ Utrecht. 1980.
6Fojisaki Y, Morimoto T, Sugimori T, et cd. Experimental infection of pigs with porcine parvovirus[J]. Nati lnim Health Q(Tokyo),1975, 22:205 -206.
8Biront P, Leunen JI, Vendeputte J. Inhibition of virus replication in the tonsils of pigs previously vaccinated with a Chinese strain vaccine and challenged oronasally with a virulent strain of classical swine fever virus [ J]. Vet Microbiol, 1987, 14 : 105 - 113.
