Infections with Erysipelothrix rhusiopathiae in poultry flocks

Abstract

Severe disease outbreaks of erysipelas in poultry flocks are caused by infection with the bacterium Erysipelothrix rhusiopathiae. This disease occurs in a wide range of poultry, including turkey, broiler chicken, hen, goose, and pheasant flocks. Erysipelas usually follows an acute course in birds, in the form of sepsis. Infections with E. rhusiopathiae occur through damaged skin or mucous membranes. The symptoms that occur just before death include unsteady locomotion and a lack of coordinated movement. A chronic form of bacterial infection primarily occurs in turkeys that have been vaccinated against erysipelas, and, in addition to affecting the joints, endocarditis can occur. Usually, carcasses are in good condition and correctly muscled, although ecchymosis might be visible in subcutaneous fat and thigh muscles, while internal organs become enlarged, such as the liver, spleen and kidneys. Histopathological tests indicate major vascular changes in the parenchymatous organs. Points of necrosis related to the infarctions of the large vessels are rarely observed, whereas spilled degenerative changes of parenchymatous organs are more likely to be observed. Turkeys are the only species of poultry for which vaccines against erysipelas have been registered; however, this vaccination is also effective for other poultry. E. rhusiopathiae is mainly sensitive to penicillin, but also responds to cephalosporins, tetracyclines, quinolines, clindamycin, erythromycin, and piperacillin.