Under the same conditions ,the challenge test showed that four strains of bullfrogs pathogens (Yersinia kristensenii,Proteus mirabilis, Acinelobacter calcoaceticus and Edwardsiella tarda) could make the bullfrog and frog fall ill and cause death and that the symptoms and pathological changes of the two kind frogs caused by the same pathogenic bacterium were the same.It proved that the frogs were easily infected with bullfrogs common infectious diseases,and were one of the impo...