Health Protection Agency investigates national outbreak of salmonella

Oct 5 2004

The UK's Health Protection Agency, together with colleagues in the NHS and Local Authorities, has been carrying out an investigation into a national outbreak of Salmonella.

The outbreak, involving a relatively rare strain of the bacteria called Salmonella Newport , has mainly affected people in separate outbreaks in North East Lincolnshire, Birmingham and the West Midlands, Northern Ireland and the Isle of Man. To date, over 350 cases have been reported.

Dr Bob Adak, who is leading the national investigation for the Agency, said “We usually only see around 150 cases of this particular strain of Salmonella each year, so when these separate outbreaks were reported to us we knew something was happening. Our Salmonella Reference Laboratory carried out additional testing and has found that the strains of the bacteria are identical.

“Investigations into the cause of this outbreak have been carried out both on a local and a national level using questionnaires to establish any common foods eaten in the days before people became ill. In some of the local investigations the results suggest that consumption of lettuce from various catering fast food and take-away premises are the likely main cause of the outbreaks.

“The HPA have been working closely with the Food Standards Agency to look at the supply chain of these salad products and to see if we can identify where they became contaminated. It is possible that the foods responsible for these outbreaks have now been used up, however it is important to investigate where they became contaminated, to establish whether the outbreak is ongoing, and to prevent this happening again in the future”

Judith Hilton, Head of Microbiological Safety at the Food Standards Agency, said: “Food Standards Agency advice is that the risk of food poisoning can be reduced by good food hygiene practices. These include thorough washing and preparing of lettuce away from other foods to avoid cross-contamination and storing it in the fridge before it is served, because at warmer temperatures salmonella can grow. A clean kitchen and good personal hygiene are also obviously important"

What is salmonellosis?

Salmonellosis is an infection with a bacteria called Salmonella. Most persons infected with Salmonella develop diarrhea, fever, and abdominal cramps 12 to 72 hours after infection. The illness usually lasts 4 to 7 days, and most persons recover without treatment. However, in some persons the diarrhea may be so severe that the patient needs to be hospitalized. In these patients, the Salmonella infection may spread from the intestines to the blood stream, and then to other body sites and can cause death unless the person is treated promptly with antibiotics. The elderly, infants, and those with impaired immune systems are more likely to have a severe illness.