The bacterium is pathogenic for fish, and causes the disease known as furunculosis. A recurring boil is called chronic furunculosis. In 1915 due to severe Furunculosis, (boils), was declared unfit for front. Transmission of furunculosis mainly occurs through fish-to-fish contact by the skin or by ingestion. Some clinical furunculosis survivors of an infected trout population became "A. salmonicida" carriers. Furunculosis is classified into four categories based on severity&colon; acute, subacute, chronic, or latent.