Salmonellosis is a disease caused by a Salmonella bacterium. Many different species of Salmonella exist, some of which may be carried by or cause ill health in wild birds. Some may also affect humans. The disease known as salmonellosis in garden birds is typically caused by the bacterium Salmonella typhimurium.  

Affected birds show general symptoms of ill health (such as fluffed-up plumage and lethargy) that are similar to those caused by other diseases, including colibacillosis. However, salmonellosis is more likely to occur in the winter months. 

• More detailed information about salmonellosis, including a list of scientific publications related to the disease in birds, can be found in the Garden Wildlife Health salmonellosis factsheet.

Pathology & disease spread

The Salmonella bacterium typically causes disease in the gullet, with generalised infection of the liver and spleen common in many cases. Affected birds show general symptoms of ill health (such as fluffed-up plumage and lethargy) and, since these are similar to the symptoms of certain other diseases, diagnosis invariably requires post-mortem examination.

Salmonella bacteria are somewhat robust and can persist in the wider environment for some time. The primary route of transmission is believed to be infected bird droppings which then contaminate food or water. The strains of Salmonella typhimurium that affect wild birds have the potential to affect humans and other domestic animals (including pet dogs and cats).

Species affected

Salmonellosis outbreaks tend to be sporadic in nature, more often occurring during the winter months, and typically affecting gregarious seed-eating birds like Greenfinch and House Sparrow. However, a range of garden bird species are susceptible to the disease, including other finch species such as Bullfinch, Goldfinch, Chaffinch and Siskin.

What you can do

• A few simple precautions will help limit the spread of disease in gardens and on feeders. Learn more about good garden feeding hygiene. 
• Help us understand disease in wildlife by reporting any cases that you see. Information on diseases and other forms of mortality in garden wildlife is being collected through Garden Wildlife Health.