Erysipelas - Turkey
Introduction
Erysipelothrix rhusiopathiae is the only agent thought to cause Erysipelas in avian species. It is a non-spore forming, non-motile, gram-postive rod, which does not stain acid-fast.
It is a common disease in Turkeys but is rare in the fowl.
Erysipelas is of economic importance in turkey farming as it not only causes death in the flock, but causes infertility in the male.
In humans that work with poultry, the disease is of public health significance due to its zoonotic affect. A predisposing cut can cause infection by the organism, resulting in localised infeciton or septicamia and death in people.
The organism is thought to be transmitted by contaminted material, as the source of the infection, entering the bird via breaks in the mucous membrane or skin. Fish or fishmeal has been cited as the most likely causes of infection for turkeys. The bacteria can also be transmitted in the semen of the male turkey (tom). Research into vectors of the disease has shown that the poulty red mite (Dermanyssus gallinae) can act as a resrvoir for the bacteria.
Clinical Signs
- Sudden outbreak
- Affects birds of all ages
- Sudden death without clinical signs in many birds
- Prior to death some birds may have an unsteady gait and appear weak
- Dark, purplish, swollen snoods are seen on affected males
Pathology
Gross
- Enlarged friable liver, spleen and kidney
- Lesions concurrent with septicaemia and congestion
- Petechial haemorrhage in abdominal fat
- Haemorrhage in heart muscle
- Arthritis and vegetative endocarditis and emaciation with chronic infections
Microscopic
- Sinusoidal channels and blood vessel engorgement in most organs
- Aggregations of fibrin and bacteria in capillaries and venules
- Oedma and haemorrhage in lung and heart
- Necrosis of parenchymal cells in the liver