12 August 2011
A multi-agency investigation is continuing after a link has been established between a batch of imported eggs and an outbreak of Salmonella Enteritidis Phage Type (PT) 14b infection in England and Wales.
Two hundred and twenty-one cases of Salmonella Enteritidis PT 14b infection have been reported since the beginning of this year, the majority of cases being in North West England (104 cases), the West Midlands (36 cases) and the East Midlands (26 cases).
Dr. Joe Kearney, an HPA director who chairs the outbreak control team (OCT), said: "A strain of Salmonella Enteritidis PT 14b that is indistinguishable from samples taken from the human cases was isolated from a small number of eggs that had the same batch number.
"These eggs had come from a specific shed on one farm in Spain. The Food Standards Agency (FSA) alerted the Spanish authorities and measures were taken to eliminate the risk of contamination from this source, including the culling of a flock of hens, the cleaning of the shed and the heat treatment of eggs to kill salmonella.
"No eggs with the implicated batch number have been imported to this country since the end of June. The FSA alerted Environmental Health Officers throughout England and Wales to the situation and checks were made and continue to be made on the distribution chain. Whenever eggs with the implicated batch number are found in the system, these are removed from sale. In the meantime our investigations are continuing."
Press release issued by the Communications Department, HPA North West. Tel. 0844-2251295 and select option 2.
Salmonella infection can cause watery and sometimes bloody diarrhoea, abdominal pain, headache, nausea, vomiting, and fever. It is often associated with eating foodstuffs (most commonly red and white meats, raw eggs, milk, and dairy products) that have been contaminated with the bacterium.
Some foods contain the bacterium and need to be cooked before consumption. Other foods may become contaminated directly or indirectly as a result of poor food storage or preparation practice, for example by storing raw and cooked products together or by using the same knives and chopping boards for the preparation of raw meat and foods that do not need to be cooked, such as salad vegetables.
Person-to-person spread, usually during the acute diarrhoeal phase of the illness, and contact with infected animals can also cause infection.
The illness can range from mild to severe. The elderly, infants, and those with impaired immune systems are more likely to have a severe illness. In some cases, the salmonella infection may spread from the intestines to the blood stream, and then to other body sites and can be fatal without treatment. However, death from salmonella infection is rare.
The majority of patients with salmonella infection do not require specific treatment and make a full recovery. Recovery is aided by a replacement of fluids. The advice of a health professional should be sought in cases of severe diarrhoea.
In rare events when infection spreads from the intestines to the blood stream, prompt hospital treatment is required.
Many cases of salmonella appear sporadic but outbreaks occur in the general population and in institutions.
Rates of salmonella in the UK have fallen dramatically in recent years from a peak of infection in 1997. There are many reasons for this including greater public awareness about food safety. The compulsory vaccination of UK British Lion egg-laying flocks against Salmonella Enteritidis, which was introduced in 1998, has been a major factor.
As many people with salmonella do not seek medical treatment for their illness, the number of reported cases of salmonella will be less than the actual number of cases occurring.
Salmonella can be prevented by the correct storage and cooking of foods and employing hygienic food handling and preparation procedures. Avoidance of certain foods, for example unpasteurised milk and dairy products and raw eggs will also lower the risk of illness.
Thorough hand-washing is crucially important in infection control and is essential before eating or preparing food, after handling raw meat or poultry, after using the toilet, after changing nappies and after cleaning up after others with diarrhoea. Hand-washing after contact with domestic or farm animals is also essential.
Advice on the safe preparation, storage, cooking and handling of food is available from the Food Standards Agency website - www.food.gov.uk.
Last reviewed: 12 August 2011