Erysipelas in Chickens: Symptoms, Causes and Treatment

Erysipelas is caused by Erysipelothrix rhusiopathiae, a highly persistent environmental bacterium that survives for months in soil, litter, and water.

• Erysipelothrix rhusiopathiae: A Gram-positive, non-spore-forming rod that is ubiquitous in the environment. It is carried in the intestines of many wild and domestic animals including pigs, fish, and birds. Pigs are the classic reservoir, and poultry operations near swine facilities have elevated risk.
• Routes of entry: The bacterium enters through wounds, scratches, skin abrasions, or the mucosa of the digestive and respiratory tracts. Muddy or waterlogged runs after rain concentrate environmental bacteria near the skin entry points on the feet and legs.
• Predisposing factors: Skin wounds from pecking, wire injuries, spur fighting, or rough handling provide entry points. Immunosuppression from concurrent disease, Marek's, or nutritional deficiency increases susceptibility.
• Environmental persistence: E. rhusiopathiae survives 35 days in mud, months in water, and indefinitely in preserved products. Once a farm is contaminated, the organism can persist for years in litter and soil even after decontamination efforts.
• Zoonotic transmission: Humans acquire erysipeloid (a localized skin infection, not systemic erysipelas) through cuts or abrasions contaminated with infected bird tissue, carcasses, or environmental material. It is an occupational risk for poultry handlers and slaughterhouse workers.

Erysipelas is frequently diagnosed post-mortem because sudden death is often the first sign:

• Gross necropsy findings: Septicemic erysipelas produces petechial hemorrhages on the heart and serosal surfaces, splenomegaly, and generalized vascular congestion. The comb and skin may show characteristic purple discoloration or diamond-shaped skin lesions.
• Chronic form: Surviving birds may develop vegetative endocarditis (warty growths on heart valves), swollen joints, and pale combs from anemia. These birds often die suddenly weeks later from cardiac failure.
• Bacterial culture: E. rhusiopathiae is definitively identified by culture of blood, spleen, or bone marrow on standard blood agar. The organism has a characteristic alpha-hemolysis pattern and produces a distinctive colony morphology.
• Differential diagnoses: Fowl Cholera (Pasteurella multocida) produces similar sudden death and comb discoloration. Newcastle Disease velogenic strains cause rapid flock mortality. Avian Influenza must be ruled out urgently given the mortality pattern.

Penicillin is the drug of choice for Erysipelothrix rhusiopathiae, which remains reliably sensitive to penicillin-class antibiotics.

Penicillin treatment: Procaine penicillin G at 50,000 IU/kg IM once or twice daily for 3-5 days dramatically reduces flock mortality when started promptly. Birds showing clinical signs may be treated individually. Oral penicillin in water provides group treatment for the at-risk flock.

Ampicillin or amoxicillin: Alternative options for cases where injectable penicillin is impractical. Administer at 10-20 mg/kg orally twice daily. These are more bioavailable orally than parenteral penicillin G forms.

Vaccination: Commercial bacterin vaccines are available for turkeys and may be used in chickens in endemic areas or farms with recurrent outbreaks. Killed whole-cell bacterins are administered subcutaneously and provide 3-6 months of protection. Two doses 3-4 weeks apart for initial protection.

Flock treatment: During an active outbreak, treat the entire affected flock with water-soluble antibiotics to prevent spread and reduce mortality in apparently healthy birds that may be bacteremic.

• Vaccinate flocks in endemic areas or farms with a history of Erysipelas outbreaks. A killed bacterin given at 8-10 weeks with a booster 3-4 weeks later provides meaningful protection through the high-risk production period.
• Prevent skin wounds by providing adequate space to prevent fighting, removing sharp wire or equipment, and trimming sharp spurs on roosters. Skin abrasions are the primary entry route for E. rhusiopathiae.
• Avoid co-mingling poultry with swine or locating poultry operations downhill from swine effluent areas. Pigs are the primary environmental reservoir and a proven source of flock introduction.
• Remove and lime-treat soil from runs after a confirmed outbreak. E. rhusiopathiae persists in contaminated soil for months and can reinfect replacement flocks.
• Wear gloves when handling sick birds, carcasses, or processing birds from a flock with suspected or confirmed Erysipelas. The zoonotic risk of erysipeloid is real and results in painful, slow-healing skin lesions.