News Archives |
Volume 2 No 9 ; 29 February 2008
Outbreak of infection with Salmonella Anatum in England, Wales and Scotland, ongoing analytical study
The Health Protection Agency, the National Public Health Service for Wales (NPHS) and Health Protection Scotland (HPS) are performing a case-control study to determine the cause of an outbreak of Salmonella Anatum affecting England , Wales and Scotland.
Since 1 November 2007, there have been 87 primary indigenous cases in England and Wales (E&W), and 44 in Scotland, with the most recent known onset date of 11 February 08 (Figure 1).
Figure 1 Epidemic curve of S. Anatum in England and Wales: 1 November 2007 to 27 February 2008
Figure 2 Age and sex distribution of S. Anatum cases in England and Wales: 1 November 2007 to 27 February 2008
Cases are distributed across Wales and nine HPA regions in England , with the greatest concentration in the North West (33%), the North East (16%) and Yorkshire and Humberside (15%) (Table 1).
Table 1 Incidence of S. Anatum by region, 1 November 2007 to 27 February 2008
Country/Region |
No. cases |
Incidence |
North West |
29 |
0.423 |
Yorkshire and Humber |
14 |
0.272 |
North East |
13 |
0.509 |
West Midlands |
7 |
0.130 |
South West |
7 |
0.137 |
East |
2 |
0.036 |
East Midlands |
2 |
0.046 |
South East |
1 |
0.012 |
London |
2 |
0.027 |
Wales |
10 |
0.337 |
Detailed interviews were conducted with eligible cases between 23 December 2007 and 30 January 2008. On the basis of the evidence collected, the outbreak control team has decided to undertake a case-control study to test specific hypotheses raised from the trawling interviews. The collaborative study will involve a team including members from HPA, HPS and NPHS.
ONS data on healthcare associated infection mortality
Latest statistics from the Office for National Statistics identified a 72 per cent increase between 2005 and 2006 in the number of death certificates in England and Wales mentioning Clostridium difficile infection [1] . This increase follows the reissuing of guidance on completion of death certificates in 2005, with particular emphasis on the need to include healthcare-associated infections on the certificate where relevant to the patient's death [2]. Mandatory surveillance data for C. difficile associated disease in patients 65 and over increased by 7% over this same period [3].
The total number of death certificates on which C. difficile was mentioned was 6,480 in 2006, with C. difficile selected as the underlying cause of death in around half ( 3490; 55 % ) of these cases. Of all deaths occurring in NHS general hospitals between 2002 and 2006, 0.99% involved C. difficile.
Deaths involving C. difficile are predominantly among older age groups. Mortality rates in 2006 for deaths in the 85 and over age group were 2,795 and 2,785 deaths per million population for males and females respectively. Mortality rates were 0.2 and 1.3 deaths per million population for males and females respectively in the under 45 age group.
In contrast to the above trend in deaths certificates with mention of C. difficile , deaths with mention of MRSA showed little change between 2005 and 2006 [4].
References
[1] Report: deaths involving Clostridium difficile : England and Wales, 1999 and 2001-06. Health Stat Q 2008; 52-56.
[2] Office for National Statistics' Death Certification Advisory Group. Guidance for doctors certifying cause of death. London: Office for National Statistics, 2005.
[3] HPA. Surveillance of Healthcare Associated Infections Report 2007. London : Health Protection Agency; 2007.
[4] Report: deaths involving MRSA: England and Wales, 1993-2006. Health Stat Q 2008; 57-62.
An upgraded Health Protection Agency website, www.hpa.org.uk, is due to be launched mid-afternoon on Friday 29 February. The site's new design aims to make information about the Agency's activities more easily accessible and allow the content to be more speedily updated. HPR readers are invited to visit the new site and complete the online survey which can be accessed via the HPA Website Feedback link at the bottom right hand corner of the home page. HPR will remain available in its current format at www.hpa.org.uk/hpr.