Infections of fish with A. salmonicida results in furunculosis

infections of fish with A. salmonicida results in furunculosis, which is characterized by boil-like lesions on the skin. Following strict management of the disease in the UK, the prevalence of the infection has declined drastically. The A. salmonicida is the most common of the three subspecies causing the disease. The bacilli are characterized by pigment production during their growth, producing bipolar staining characteristics (Rowan 742). Cultural characteristics of the organism include brown pigmentation, with the cells growing best at 18 to 25^oC producing raised colonies that are tiny and white in color. Biochemically, the organism is positive to oxidase test and does not produce any gas while fermenting glucose. Its pathogenicity is aided by the production of endotoxins. The organisms primarily infect fish and are found in carrier fish or in infected water bodies forming abundant reservoirs. Following horizontal transmission in contaminated water or carriers, A. salmonicida causes subacute to acute lesions that may be chronic depending on the virulence of the infecting strain, environmental temperature dose and host resistance to the organism.