Thursday, April 15, 1999 Published at 23:59 GMT 00:59 UK
Stomach infections: The true picture
Stomach infections are usually mild, but can be fatal
One in five people in England suffer from stomach upsets like salmonella every year, according to government-backed research.
The figure is much higher than recorded figures suggest.
One in six go to the doctor when they get a stomach upset, but only one in every 136 cases is reported to the Public Health Laboratory Service (PHLS), which is responsible for national monitoring of infectious disease.
This means its figures are a huge underestimate of the presence of infectious disease in the community.
Stomach infections account for more than 300 deaths and 35,000 hospital admissions in England and Wales every year.
The £2m study, which covered around 10,000 patients from 70 GP practices across England, was commissioned as part of an effort to track the extent of infectious diseases such as salmonella, campylobacter and rotavirus.
Patients were surveyed over a six-month period and people who developed diarrhoea and vomiting provided specimens for laboratory investigation.
The study, published in the British Medical Journal, found that there are an estimated 9.4m cases of infection in England every year.
Infections caused by common viruses were much more likely to be under-reported than those caused by food poisoning bugs like salmonella.
But in two thirds of cases the cause of the infection could not be detected.
Figures published by the PHLS show there has been a sharp rise in cases of salmonella and campylobacter in the last decade.
Professor Liam Donaldson, the government's chief medical officer, said: "The study provides, for the first time, a complete picture of the true incidence of all intestinal infectious disease (IID) in the community, not just cases of food poisoning.
"We commissioned the study because we were aware that there was under-reporting of cases of IID and felt it was important to have a better idea of the true extent of illness.
"Now we have a clear indication of the size of the problem and this will help us to tackle it."
The researchers say more understanding is needed of what causes infection so that better prevention strategies can be planned.
They also want the national surveillance system to be improved so it can monitor the problem more accurately.
Dr Roger Skinner, head of the Department of Health's Food Safety Policy Branch, said: "The findings demonstrate that we have a problem here ... the government needs to drive home the key messages of food hygiene, and take that right through the food chain, from the home to the farm."
A spokesman for the PHLS said the study showed the need to emphasise basic rules of personal hygiene as well as the importance of taking care over food preparation.