Erysipelothrix rhusiopathiae is a type of bacteria that causes erysipeloid, a skin condition that people can develop after contact with infected fish, poultry, or pork. Healthy fish often carry the bacteria on their scales with no signs of illness.
People, especially fish handlers, can become infected through open wounds on their hands. Affected people will usually develop a warm, raised, red, and intensely itchy area of skin at the site of the contaminated wound. If the infection spreads from the skin to deeper tissues, arthritis or more serious signs of illness (fever, weakness, muscle aches, headaches, etc.) may develop.
People who handle fish regularly should wear gloves and wash their hands often to reduce the risk of this disease.
From the Center for Disease Control and Prevention (CDC)