Veterinary surveillance: Salmonella
What is salmonella and why is it important?
Salmonella are bacteria which can cause disease in animals and people. They are one of the most important causes of food poisoning. People and animals may become ill if they eat food containing the bacteria. The illness may be mild or it can be very severe. Some animals and people are infected without being ill at all. They are known as “carriers” and can still spread the disease to others.
Infected animals may produce meat, milk or eggs containing salmonella. The bacteria may spread to clean food if it is not handled hygienically. Outbreaks of food poisoning may cause food poisoning alerts. Proper cooking kills salmonella.
Salmonella is present in the faeces of infected people and animals. Manure from infected livestock can contaminate water. The normal treatment of drinking water supplies removes the bacteria. Vegetable crops may carry salmonella if untreated water is used for irrigation.
People can also become infected by handling infected animals.
What species are affected?
The bacteria live in the intestines of many different sorts of animals as well as in people. Farm animals, pets, horses, birds and reptiles like tortoises can all be infected. Infection may spread between people as well as from animals to people.
How do we look for salmonella in animals?
Vets may send samples to a laboratory from animals they see. This may
be to help diagnose the cause of an illness. Sometimes animals which look
healthy may be tested for screening. If the laboratory finds salmonella
in a sample from a farm animal or a horse, they must tell us.
Owners of poultry breeding flocks must test their flocks regularly for
salmonella. They must tell us if they find any salmonella.
Some pig farmers take part in a voluntary testing scheme called the Zoonoses Action Plan (ZAP). Samples are taken at the abattoir from pigs which have been slaughtered for human consumption.
The Health Protection Agency (HPA) may find salmonella in people with food poisoning. Sometimes the medical authorities may suspect that the bacteria came from a particular farm. We can then help them track down the infection by taking samples on the farm.
Results of surveillance
The results of testing are used to help the owners control disease in their animals. Information may be passed to the medical authorities when necessary. Control measures are sometimes enforced by law.
All the laboratory results reported to us from Great Britain are included in an annual report. Recent interesting cases are reported in monthly reports in the Veterinary Record.
Further information
More detailed information is given in the Salmonella
profile 
(74 KB) . For enquiries about particular salmonellas, contact the VLA
at: fbzs@vla.defra.gsi.gov.uk.
Information on other diseases which can affect both animals and people
is given on our zoonoses
page. The Food Standards Agency monitors salmonella in food and provides
advice on proper food cooking.
- Glossary
- Other websites - These sites may be useful if you are interested in further information about veterinary surveillance in the UK. Please note that Defra does not necessarily endorse the content, information or opinions of these sites.
- Code of Practice for the Control of Salmonella
- Annual report on salmonella in livestock
- Laboratories approved
to test for Salmonella
(92 KB)
- Health Protection Agency
- Food Standards Agency
- Zoonoses
Action Plan
Page last reviewed:
11 August 2006
Page last modified: May 25, 2005