Erysipelas

Affected flocks may suffer from egg production losses and high mortality.

Etiology

Erysipelas is caused by the bacteria Erysipelothrix rhusiopathiae. This is a facultative, anaerobic bacterium. E rhusiopathiae stains gram-positive but tends to decolorize in older cultures. This opportunistic bacterial pathogen is small, rod-shaped, nonmotile, non-spore-forming, and does not produce toxins.

Susceptibility of the agent

E. rhusiopathiae is susceptible to most commercial disinfectants. Heat (55 °C for 15 minutes) completely inactivates the bacteria. E. rhusiopathiae is resistant to several food preserving techniques such as salting, pickling, and smoking.

Occurrence

Erysipelas occurs worldwide in a wide range of poultry, being most common in turkeys and free-range layer chickens. The disease is most common in mature animals, but it has also been described in the young. Erysipelas can also affect humans and it is considered an occupational disease in personnel handling flocks infected with the bacteria.

Pathogenesis

The pathogenesis concerning infections with E. rhusiopathiae has not been completely elucidated. It is believed that bacterial penetration via wounds or cuts is needed. However, the presence of E. rhusiopathiae in intestinal contents supports involvement of the fecal oral route. Adhesion to host cells via virulence factors that enable E. rhusiopathiae to interact with the host cells seem to be essential for infection and invasion.

Clinical manifestations

The onset of the disease is typically sudden. A few animals may be found dead. Other animals may be depressed and reluctant to move. A few birds may be seen with respiratory signs and / or diarrhea. The most visibly sick birds usually die within a few hours. In some infected turkeys marked inflammation of the snood or dewlap can be seen (Picture 1).

Picture 1. Marked inflammation of the snood and dewlap of a male turkey. Picture credit: AAAP.

Necropsy findings

Organs appear swollen, splenomegaly (enlargement of the spleen) is often evident. Hemorrhages are seen in pericardial fat, on pericardium, and on serosal surfaces and muscles. Purulent arthritis and endocarditis can be detected in chronic cases.

Diagnosis

Demonstration of E. rhusiopathiae in affected tissues is needed for diagnosis. Samples for bacteriological investigation can be retrieved from the spleen and liver.

Relevant differential diagnosis

Fowl cholera, colisepticemia, salmonellosis, virulent Newcastle disease.

Prevention and Treatment

If erysipelas is common in an area, turkeys should be vaccinated at 8-12 weeks of age. This disease is generally treated with the simultaneous administration of antibiotics and a vaccine.

Text was prepared by G. Lorenzoni and L. Loughlin

References

Avian Diseases Manual.  8^thed. The American Association of Avian Pathologists.

Diseases of Poultry, 13thed. AAAP. Whiley-Blackwell.

Bisgaard, M., & Olsen, P. (1975). Erysipelas in egg‐laying chickens: Clinical, pathological and bacteriological investigations. Avian Pathology, 4(1), 59-71.

Swan, R.A., and M.J. Lindsey. 1998. Treatment and control by vaccination of erysipelas in farmed emus (Dromaius novo‐hollandiae). Australian veterinary journal, 76(5), 325-327.

Venditti, M., V. Gelfusa, A.Tarasi, C. Brandimarte, and P. Serra. 1990. Antimicrobial susceptibilities of Erysipelothrix rhusiopathiae. Antimicrobial agents and chemotherapy, 34(10), 2038-2040.