2Alderton M R, Borland R, Coloe P 3. Experimental reproduction of porcine proliferative enteritis[3].J Comp Aath, 1992,106:159-167.
3Joens L A, Nihbelink s, glock R D. Induction of gross and microscopie lesionsof procine proliferative enteritis by Lawsonia intracellaris[J].AJYR, 1997,58:1125-1131.
4McOrist S,.Lawson G H K, Rowland A C. et al. Early lesions of proliferative enteritis in pigs and hamsters [J].Vet Pathol, 1989,26:260-264.
5Knittel J, Kroll J, Mathes Met al. Efficacy of an avirulent Lawsonia intracellularis vaccine in swine[M]. Proc IPVS. 2000:16,24.
6Collins AM, van Dijk M, McOrist Set al. Strategic medication and development of immunity to Lawsonia intracellularis[M].Proc IPVS. 2000:16,30.