ABSTRACT
This chapter discusses two bacterial diseases that are most often associated with cyprinids are "carp erythrodermatitis" (CE) and "ulcer disease of goldfish" (UDG), and infections caused by these pathogens in other species of fish. Other bacterial pathogens that cause disease in cyprinids include motile Aeromonas septicemia (MAS) and columnaris. Diagnosis of atypical Aeromonas salmonicida infections is accomplished by noting the presence of clinical signs including ulcerative skin lesions, etc. A. salmonicida achromogens is isolated from necrotic musculature, or hemorrhagic, inflamed skin lesions, and occasionally from the visceral organs of carp or goldfish. The epizootiology of atypical nonmotile Aeromonas infections is similar in most species of fish, especially in terms of seasonal and temperature relationship, age of susceptibility, mortality patterns, and location of the causative organism in infected fish. Handling, crowding, or injuries to the skin of carp and goldfish should be kept to a minimum during critical periods to avoid CE and UDG infections.
