2Nicolet J,de Meuron P A.Isolation and characterization of mycoplasmas in the calf pneumoenteritis syndrome[J].Zen- tralbl Veterinarmed B,1970,17(10):1031-1042.
5Haesebrouck F,Chiers K,Van Overbeke I,et al.Actinoba- cillus pleura pneumoniae infections in pigs:the role of viru- lence factors in pathogenesis and protection[J].Vet Microbiol,1997,58(2-4):239-249.
6Gottschalk Mf Broes A,Mittal K R,et al.Non-pathogenic Actinobacillus isolates antigenically and biochemically similar to Actinobacillus pleuropneumoniae:a novel species?[J].Vet Microbiol,2003,92(1-2):87-101.
