Pullorum disease

Pullorum disease of chickens is a bacterial infection caused by Salmonella enterica subspecies enterica serovar Gallinarum biovar Pullorum (Salmonella pullorum). In its acute form, Pullorum disease is almost exclusively a septicaemic disease of young chickens. However, the organism may also be associated with disease in turkey poults and may be carried subclinically or lead to reduced egg production and hatchability, plus a range of atypical signs in older birds. 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. Clinical signs in chicks and poults include anorexia, diarrhoea, dehydration, weakness and death. In mature birds, Pullorum disease is less severe but decreased egg production, poor hatchability and some increased mortality may occur. Salmonella pullorum is host adapted to avian species and are considered to pose a minimal zoonotic risk.