The epidemiology of foodborne disease in England and Wales.

1 OUR changes in the epidemiology of foodborne diseases were much publicized in 1989: the epidemic of salmonellosis due to Salmonella enteritidis phage type 4, the rise in campylobacter enteritis, the discovery of food as a vehicle of infection in some cases of listeriosis and the large outbreak of botulism in north west England and Wales. However, other important changes took place during the 1980s which attracted less public attention: outbreaks of viral foodborne disease became common, yersiniosis increased, haemorrhagic colitis was first recorded and giardiasis and cryptosporidiosis came into prominence. The main food and waterborne diseases of the past remained rare and those cases that were documented were usually imported. Salmonellosis is the most important foodborne disease in England and Wales, measured in overall morbidity and mortality. In 1989 there were over 25 000 laboratory reported infections and 57 (provisional) registered deaths. Although usually a mild gastrointestinal infection and often symptomless, about 1.50o of reported cases develop systemic complications such as septicaemia, meningitis and bone and joint abscesses.' In the last decade there have been two major epidemics. The first, in the early 1980s, involved Salmonella typhimurium. This has now declined and was probably caused mainly by bovine infection.' The second epidemic, unprecedented in scale, involved S enteritidis phage type 4. This emerged in the mid 1980s and was caused by infection in poultry.2 Sixty per cent of chickens bought in retail outlets, and the yolk of one in 1000 intact eggs from flocks implicated in outbreaks were shown to be contaminated.2 Many outbreaks were traced to poultry meat and shell eggs, and case-control studies demonstrated an association of sporadic cases with these foods.2 Extensive veterinary control measures were introduced3 and wide publicity given to food hygiene. Although it is too early to assess the effect of these measures it is encouraging that the increase in the epidemic in 1989 and early 1990 was substantially less than that in 1988. Campylobacter enteritis is now the most common laboratory diagnosed cause of acute gastrointestinal infection-in 1989 there were nearly 33 000 reports in England A and Wales. Reports increased as new tests were developed and became widely available in the late 1970s, but the more than threefold rise during the 1980s was probably partly due to a real increase in the incidence of the infection. Although there were a few milkborne and waterborne outbreaks and some were traced to poultry …