Measuring foodborne illness levels
Tuesday 29 March 2011
The Food Standards Agency monitor trends in foodborne disease caused by key pathogenic (disease-causing) bugs in the UK. These trends are monitored through laboratory-confirmed cases of illness.
How foodborne illness levels are measured
Cases are confirmed when a stool sample is provided by someone suffering from food poisoning symptoms and is sent to a laboratory by a GP or other health professional. However, even if a foodborne germ is found we cannot always be sure it has come from food that has been eaten, it could be from contact with some else suffering from foodborne disease. Also, not all people suspected of having food poisoning provide a stool sample for testing. This means we can't be sure exactly how many cases of food poisoning there are, but there are ways in which we can make reasonable estimates of trends and tell whether the number of cases is going up or down. Although these confirmed cases only represent a fraction of the total, this system does provide a consistent indication of trends in some of the key foodborne pathogens the Agency monitors.
Since 2000 the Agency has monitored the changes in foodborne disease using confirmed laboratory notifications of salmonella, campylobacter, E. coli O157 and Listeria monocytogenes.
Trends in foodborne disease
Between 2000 and 2005 there was a considerable reduction (19.2%) in the levels of foodborne disease; however, since then cases of foodborne illness have remained relatively stable, though increasing in recent years since 2005. This increase is largely due to a substantial increase in the number of cases of campylobacter infection, which has occurred in all UK countries. It is currently unclear whether this increase is due to a true increase in incidence, an increase in reporting, or a combination of the two. We are working closely with other relevant parties (e.g. Health Protection Agency, Health Protection Scotland, National Public Health Service for Wales and Public Health Agency for Northern Ireland) to better understand this increase.
The Agency is continuing to monitor confirmed cases of salmonella, campylobacter, E. coli O157 and L. monocytogenes as part of the 2010–15 foodborne disease strategy. In addition, we will monitor confirmed cases of norovirus, which is estimated to cause approximately 200,000 cases of foodborne disease each year in England and Wales alone.
Until 2009, the Agency reported cases of Clostridium perfringens, but it is difficult to estimate disease burden from reported cases as the disease is usually mild and the number of cases recorded each year is low, therefore the Agency will no longer be reporting cases of C. perfringens.
Laboratory confirmed cases of foodborne illness acquired in the UK: 2000 to 2010
| Campylobacter | Salmonella | E. coli O157 | Listeria monocytogenes | Norovirus** | |
|---|---|---|---|---|---|
| 2000 | 52,567 | 12,784 | 1,035 | 114 | – |
| 2001 | 49,287 | 13,935 | 916 | 162 | – |
| 2002 | 43,355 | 12,736 | 748 | 160 | – |
| 2003 | 41,283 | 13,207 | 777 | 248 | – |
| 2004 | 39,822 | 12,344 | 819 | 230 | – |
| 2005 | 41,882 | 10,220 | 1,029 | 220 | 4,653 |
| 2006 | 42,360 | 10,970 | 1,146 | 208 | 7,320 |
| 2007 | 46,733 | 10,570 | 974 | 254 | 8,495 |
| 2008 | 44,842 | 8,542 | 1,096 | 205 | 9,438 |
| 2009 | 52,617 | 7,677 | 1,160 | 234 | 10,377 |
| 2010* | 56,767 | 6,613 | 924 | 174 | 15,529 |
*Figures for 2010 are provisional figures provided by the HPA. The confirmed figures will become available in autumn 2011.
**Norovirus figures include both community and hospital-acquired infections, as the HPA laboratory reporting system cannot differentiate between them.
More information on trends in foodborne disease can be found via the links in the ‘See also’ section below.