Pullorum Pathology

The nature, cause, origin, and progress of Pullorum.

Pullorum disease of chickens is caused by Salmonella enterica. The disease is almost exclusively a disease of young chickens. However, the organism may also be associated with disease in turkey poults.

The organism can persist outside the body for many months. Infected hens pass the bacteria through their ovaries to the eggs.

The first indications of the disease may be reduced hatchability, a large number of dead-in-shell chicks, or chicks which die shortly after hatching. Surviving chicks may appear weak and drowsy at 4-5 days of age, with white pasty diarrhea around the vent. Respiratory signs may occur, and losses peak at 2-3 weeks of age. Surviving birds may show no signs, but may be carriers.

Ovarian transmission is a major route by which the organism can spread. Game birds and ‘backyard’ poultry flocks may act as reservoirs of infection, and wild birds may act as vectors for the organism and as such are important in the epidemiology of the disease.