Gangrenous (necrotic) dermatitis

Occurrence: Everywhere that poultry are reared on built up litter.
Species affected: All poultry reared in confinement.
Age affected: mostly young birds
Causes: Clostridium septicum, E. coli, and S. aureus.
Effects: Signs include loss of feathers, low mortality, dead birds decompose quickly, pale
combs and wattles. Lesions are reddish, greenish, necrotic skin usually devoid of feathers, overlying wings, breast, abdomen, or legs.

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Causes

Clostridium septicum, E. coli, and S. aureus in the litter. The disease results from immunosuppression, which increases incidence and severity of dermatitis. Immunodepression may be due to a prior infection with IBDV, MDV, ALV, or CAV infection(s) or mycotoxin ingestion.

Mode of transmission

Transmission is by contact with infected wet, caked litter. The disease often occurs in immunosuppressed birds.

Clinical signs

Signs include loss of feathers, low mortality, dead birds decompose quickly, pale combs, and wattles. Depression, incoordination, inappetence, leg weakness, and ataxia (can’t move) can also be seen.

Gangrenous (necrotic) dermatitis

Postmortem lesions

Lesions are reddish, greenish, necrotic skin usually devoid of feathers, overlying wings, breast, abdomen, or legs. Gas may be given off upon palpation of skin, and blood‑tinged edema (watery fluid). It may affect muscle under skin causing discoloration. Anemia (paleness due to lack of red blood cells), retained yolk sacs, discrete white foci in the liver may also be seen.

Diagnosis

Diagnosis is by post-mortem lesions, which include congestion, hemorrhage and necrosis of skin with intra lesion bacteria under the microscope. Bacteria can be isolated anaerobically on 2.5% blood agar.

Prevention

Clean out house and add new litter. Proper vaccination against IBDV, CAV, and MDV, prevent mycotoxin formation in the feed, to prevent immunosuppression.

Treatment

Antibiotics in starter feed to reduce bacteria.