Salmonella

There are a large number of salmonella bacteria that can cause disease.

Salmonella is a major cause of food-borne illness within the world. Salmonellosis is an infection of the bowel that can affect all species of animals and people. Illness in people caused by salmonella bacteria is sometimes called 'food poisoning'.

Strains

Some strains of salmonella in animals must be reported under legislation and these detections should be reported to Biosecurity Queensland. The particular strains are:

• Salmonella abortus equi—prohibited matter
• S. abortus ovis—prohibited matter
• Salmonella Gallinarum—prohibited matter
• Salmonella Pullorum—prohibited matter
• Salmonella Enteritidis infection in poultry—category 1 restricted matter

Salmonellosis can occur worldwide.

This disease can occur in all species of livestock but is more common in cattle and pigs.

Clinical signs include septicaemia, enteritis, diarrhoea (often blood-stained) and abortion. Acute illness can result in high mortality rates, especially among young animals. Animals that recover can become carriers and excrete the bacteria in their faeces. These animals are a serious cause of disease spreading to other animals.

About 2,000 cases in people are reported to health authorities in Queensland every year, but the actual number of cases is likely to be considerably greater.

Contaminated food of animal origin (e.g. milk, eggs, meat and poultry) is the primary source of infection in humans.

People usually become infected by eating contaminated foods that have not been cooked thoroughly. Infection can be spread from an infected person to other people if strict hygiene is not observed. Signs of illness generally develop 12–72 hours after ingestion of contaminated material. Symptoms include fever, headache, diarrhoea and sometimes vomiting. Infants and the elderly are at greater risk as diarrhoea and vomiting can lead to severe dehydration.

It is more common in summer than winter.

Prevention in animals

Farm biosecurity procedures play a large part in controlling this disease. Buying animals in poor condition, particularly if they have diarrhoea, should be avoided. Known carriers of salmonella bacteria should be culled. Strict attention to hygiene, drainage and disinfection will help prevent the spread of disease.

Prevention in humans

To avoid the risk of salmonellosis it is important to:

• wash hands with soap and water after handling animals, birds or pets
• avoid cross contamination of raw or cooked foods with uncooked foods
• cook food thoroughly before eating
• avoid eating or drinking foods containing raw eggs
• wash fruit and vegetables before eating
• wash hands with soap and water after changing nappies or going to the toilet.

Treatment

Recovery usually occurs within 5–7 days without any specific treatment. Oral replacement fluids are advisable to prevent dehydration. Antibiotics are not usually prescribed. Infections that result in severe dehydration or septicaemia may require hospital treatment.

Monitoring and certification program

The Salmonella Enteritidis monitoring and certification program is not mandatory but forms part of securing a safe food product. Egg producers are encouraged to curb salmonella food-borne related illness. Please contact us for information about the program.