Studies on the immune response of rabbits for some types of bacterial antigens

The aim of this study was directed to make complete bacteriological and immunological studies on some strains of E. coli and Salmonellae known to be highly pathogenic to rabbits in Egypt.The pathogenicity of E. coli 0128 : K67 was studied by two methods ; oral infection and ligated intestinal loop. By oral infection ; E. coli caused depression , off food anddiarrhoea with 50%o mortality. The post mortem lesionshowed severe catarrhal enteritis with whitish grey necroticpatches on the mucous membrane of caecum and colon. Thetoxigenicity of the organism was also proved by the ligatedintestinal loop .In case of S. tvphimurium, the infected rabbits showed symptoms of illness with yellowish diarrhoea, the mortalityrate was 40% and the post mortem examination showed catarrhal gastroenteritis with white necrotic focci in spleen, liver and Peyer’s patches . While in S.enteritidis , theinfected rabbits showed more severe symptoms with 60%) mortality Post mortem examination revealed haemorrhagic enteritis _ necrotic focci in the internal organs withcongestion in the lungs .: