Abstract: In this work, water-soluble and W/O emulsion microcapsule vaccines were prepared with sole EHEC O157H7 strainmixed with other 11 pathogenic bacterial strains from the three genera. Namely salmonella, Shigella and Escherichia. Hol-stein cows in their later 2 month of gestation were vaccinated/immunized respectively by prior prepared vaccines, and theagglutination titer of EHEC O157H7 specific antibody in the cows milk with respect to control group was detected through theentire period of lactation and the next lactation. The immunoresponse, clinical symptoms after vaccinating and potential badeffects of the O157H7 vaccines were surveyed. The results indicated that the immunogenic effects of vaccine II( w/o emulsionmicrocapsule vaccine) were remarkablely good, the titers were all above 27, the high anti-O157H7 titer level could sustain to thenext lactation, and no obvious bad effects were observed. Surprisingly, about 30% milk samples in control group had positiveimmunoreactions to the EHEC O157H7, and the highest EHEC O157H7 specific antibody titer was 27 , This kind of phenomenonhas never reported in China yet. EHEC O157H7 is the major pathogen of hemorrhagenic colonitis (HC), the history of outbreaksof the disease in the world wide in recent two decades, as well as the epidemic and clinical feature of the EHEC O157H7caused diarrhea were briefly reviewed.

Key words: EHEC O157H7 , Immune milk , Vaccinate/immunize , Agglutination titer