PROTECTION AGAINST CARP ERYTHRODERMATITIS FOLLOWING BATH OR SUBCUTANEOUS EXPOSURE TO SUBLETHAL NUMBERS OF VIRULENT AEROMONAS-SALMONICIDA SUBSP NOVA

A bath challenge system was used to infect carp, Cyprinus carpio L., w ith Aeromonas salmonicida subsp. nova, the causative agent of carp ery throdermatitis. Bath-challenged fish became infected with the bacteriu m exhibiting typical signs of the disease. Carp that were sublethally bath exposed became infected and exhibited some skin lesions, but afte r one week, these quickly healed and the animals fully recovered from the infection. Naive fish that had not been previously exposed to the bacterium had mortalities of 100% when infected by the subcutaneous ro ute and 40-60% by the bath route of infection. Carp that received subl ethal infections were able to withstand subsequent lethal infections a nd recover regardless of the route of infection. Sublethally bath-expo sed carp were protected from subsequent lethal challenges of A. salmon icida subsp. nova for at least 5 months.