Gangrenous dermatitis (necrotic dermatitis)
A bacterial condition in chickens caused by spores of Clostridium septicum, sometimes that of Cl. novyi / Cl. edematiens and occasionally by non-spore-forming Staphylococcus aureus. Morbidity may be up to 50% with high mortality. The disease occurs after entry of the pathogen through breached skin of birds. Immunosuppression is generally a predisposing factor particularly with congenital chicken infectious anaemia virus or IBD virus infection.
Symptoms and lesions: Gangrenous skin, severe cellulitis especially of thighs, wings, wattles and mortality represent a typical clinical picture. Post-mortem lesions include patches of gangrenous dermatitis with underlying emphysematous cellulitis, usually over wings and breast, sometimes thighs and other parts, often with sero- sanguinous fluid. Swelling and infarction of the liver and spleen with focal necrosis in liver are the other lesions noticed.
Diagnosis: Clinical signs and lesions in an ill-managed farm with history of immunosuppression is a good indicator of the condition. Isolation of organisms from the tissues of fresh carcass when corroborated with the above findings may confirm the etiology.
Prevention and control: Avoiding skin trauma and immunosuppression alongwith good hygiene, nutrition and management are adequate to keep the disease away from flock.