author(s)
Alaa N Lateef, Khalid M hammadi and Ahmed J Mohammed

abstract
This study was conducted to investigate the clinico-pathological changes in rabbits after infected experimentally with E. coli O157: H7 isolated from human. This study was carried out on sixty domestic rabbits of both sexes in two experiments, in the first experiment, 20 rabbits were used to estimate the infective dose of E. coli O157: H7 and the remaining (40) rabbit were infected with the estimated infective dose of E. coli O157:H7. The results showed that the infective dose (ID) of E. coliO157: H7was (5×10^-8C.F.U/ml) which appeared the clinical signs of E. coli without mortality in this group. Post inoculation, all rabbits were examined clinically, and postmortem changes (macro and microscopic) were also examined. With isolation of the organism from different organs at 24,48,72,96, 120, 144 and 168 hours post infection. The body temperature, heart and respiratory rates were elevated accompanied with diarrhea, depression and loss of appetite. The lesion included the internal viscera of rabbits which show enlargement and congestion. The intestine revealed proliferation in the payer patch and infiltration of mononuclear cell. Other organ like brain, spleen, Lung, liver and kidney revealed congestion of blood vessels and infiltration of mononuclear cell.