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Final Issue: Volume 16 Number 51
Published on: 21 December 2006
Final Issue in PDF
Last updated: Volume 15, No.9 (PDF file, 624 KB)
The United Kingdom (UK) Health Departments’ published their influenza pandemic plan on 1 March 2005. The Health Protection Agency plan, which was issued on the same day, is designed to operate alongside the Health Departments’ contingency plan and sets out how the agency will protect the public's health in the event of a flu pandemic affecting the UK.
For further information about flu pandemics go to: <http://www.hpa.org.uk/infections/topics_az/avianinfluenza/avianflufaq.htm>.
The HPA flu pandemic contingency plan: <http://www.hpa.org.uk/infections/topics_az/influenza/pdfs/HPAPandemicplan.pdf>.
The UK Health Departments’ influenza pandemic contingency plan: <http://www.dh.gov.uk/assetRoot/04/10/44/37/04104437.pdf>.
Information on other pandemic plans across Europe is available from the European Influenza Surveillance Scheme (EISS), at: <http://www.eiss.org/index.cgi>.
The Health Protection Agency (HPA) is currently investigating a cluster of seven cases of Salmonella Virchow phage type (PT) 8 infection in the Oldham and Rochdale area of Greater Manchester. The strains, which have been confirmed by the HPA’s Laboratory of Enteric Pathogens (LEP) since 27 January 2005, were further characterised by resistance to ampicillin, furazolidone, nalidixic acid, and decreased susceptibility to ciprofloxacin (MIC: 0.5-1.0 mg/L) (R-type AFuNxCpL). Three of the cases had been in one hospital during the incubation period, and circumstantial evidence suggested that illness was linked to the consumption of pre-cooked chicken imported from Thailand and supplied to the hospital through an intermediary.
An outbreak of S. Virchow PT 8 AFuNxCpL infection in Northern Ireland in September 2004, with 15 confirmed cases, was linked to chicken sandwiches from a sandwich bar. The chicken was traced to the supplier implicated in the current cluster in England, who had imported the pre-cooked chicken from Thailand. Of 22 2.5kg bags of frozen cooked chicken examined as part of the outbreak investigation, 6 (27%) samples from two batches tested positive for S. Virchow and remaining chicken from these batches was destroyed. Two S. Virchow isolates from the chicken were sent for further characterisation and were confirmed as S. Virchow PT 8 AFuNxCpL by LEP. Batches either side of the contaminated batch (n=24) tested negative when examined on behalf of the Food Standards Agency (FSA).
Thirty-six apparently sporadic cases of S. Virchow PT 8 AFuNxCpL infection have been reported throughout England from 1 September 2004 to 28 February 2005. In a further two strains, the level of resistance to ciprofloxacin was more than 1 mg/L (=CpH).
Fourteen isolates of S. Virchow PT 8 AFuNxCpL from cases of infection in Northern Ireland and England, two isolates of S. Virchow PT 8 AFuNxCpH from cases of infection in England, a strain of S. Virchow PT 8 AFuNxCpL from a Northern Ireland food sample, and a strain of
S. Virchow PT 8 AFuNxCpL from the frozen chicken samples tested have been characterised by plasmid profile typing and by pulsed-field gel electrophoresis. All strains have an identical plasmid profile and pulsed-field pattern. These findings, together with the phage typing and antibiogram profiling results, demonstrate that the strain that caused infections in Northern Ireland in September 2004 is indistinguishable from those currently causing infections in England.
S. Virchow infection is more often characterised by bloodstream invasion compared with the majority of salmonella serotypes. In such cases antimicrobial therapy is essential. The occurrence of a strain with decreased susceptibility to ciprofloxacin is particularly concerning.
In response to these infections, the FSA (in liaison with the Department for Environment, Food, and Rural Affairs) has requested enhanced checks on pre-cooked chicken from this establishment by the border inspection post at the port of entry. In addition, the HPA will follow-up all recent cases of S. Virchow PT 8 AFuNxCpL infection to obtain additional information on transmission routes (cases with R type AFuNxCpH will also be followed-up).
For further information please contact Bob Adak (tel: 020 8327 7551; email: <Bob.Adak@hpa.org.uk> or John Threlfall (tel: 020 8327 6144; email: <John.Threlfall@hpa.org.uk> at the HPA Centre for Infections.
In response to the outbreak of Salmonella Typhimurium definitive phage type (DT) 104 resistant to ampicillin, chloramphenicol, streptomycin, sulphonamides, spectinomycin, and tetracycline (ACSSuSpT) infection in Scotland, England, and Wales (1), epidemiological investigations to generate hypotheses for disease transmission in England, and Wales were conducted by the Health Protection Agency (HPA) Centre for Infections. Nine cases, confirmed by the HPA Laboratory of Enteric Pathogens (LEP) since 1 January 2005 and resident in various parts of England and Wales, were interviewed at length using a detailed standardised trawling questionnaire. An analysis of data from eight of the nine trawling questionnaires suggested that salad items, consumed both in and outside the home, were the most likely sources of infection.
An unmatched national case-control study was undertaken to test the primary null hypothesis that infection was not associated with the consumption of salad items either inside or outside the home. Sample size calculations suggested that approximately twenty five cases and fifty controls were required to detect an Odds Ratio (OR) of four or above with 5% significance and 80% power.
All cases in England and Wales were aged 16 years and over, with a S. Typhimurium DT104 ACSSuSpT infection confirmed by LEP since 1 January 2005. Asymptomatic controls were recruited through systematic sequential dialling, based on the cases’ telephone numbers. Cases and controls with a history of recent foreign travel or contact with individuals with gastrointestinal symptoms were excluded. Interviews were conducted in the early evenings to maximise case response and to ensure that controls accurately represented the population from which the cases arose.
Twenty-five cases and 47 controls were interviewed between the 15 and 17 February 2005, of which 20 cases and 44 controls were suitable for inclusion in the analyses. There was no difference between cases and controls in terms of age (non-parametric test for the comparison of medians; P=0.27) or gender (χ2=[P=0.80]).
In a single risk analysis, cases were more likely to report the consumption of sandwiches (OR 4.73; 95% Confidence Interval (CI) 0.85-26.24; P=0.05) than controls, but no particular sandwich type was associated with being a case. The consumption of lettuce (OR 4.88; 95%CI 0.96-24.84; P=0.03), tomato (OR 15.36; 95%CI 1.36-173.74; P=0.003), or cucumber (OR 7.50; 95%CI 1.17-48.09; P=0.01) within sandwiches, however, was associated with being a case, as was the consumption of lettuce (OR 6.06; 95%CI 1.15-32.1; P=0.02) or tomato outside the home (OR 8.0; 95%CI 0.68-94.7; P=0.04). When these factors were included in a logistic regression model, only the consumption of lettuce outside of the home (OR 2.78 95%CI 1.25-6.19; P=0.008) was independently associated with being a case. When ‘iceberg lettuce consumed outside the home’ was substituted for ‘lettuce consumed outside the home’ in the final model the effect was greater (OR 7.23 95%CI 1.15-45.24; P=0.035).
Separate analyses examining where people had eaten or had bought food failed to identify a single premises type that was independently associated with being a case at the 95% significance level.
This is the second national outbreak of S. Typhimurium DT104 ACSSuSpT infection associated with the consumption of lettuce in recent years. Between 1 August and 15 September 2000, 361 people in England and Wales were ill following the consumption of lettuce outside the home (OR = 7.28; 95%CI 2.25-23.57; P=0.0006) (2). However, the implicated strain in that outbreak differed from the current outbreak strain in that it possessed a 2.0 megadalton (MDa) plasmid in addition to the 60MDa plasmid that is common to many strains of S. Typhimurium.
Furthermore, this is the fourth national outbreak of salmonella infection affecting England and Wales associated with the consumption of salad items in the last five years. In 2001, 19 cases of S. Newport infection were linked to the consumption of bagged prepared green salad (3,4). In 2004, over 350 cases of S. Newport infection in England, Scotland, Northern Ireland, and the Isle of Man were associated with the consumption of lettuce from fast-food establishments (5).
1.HPA. Outbreak of Salmonella Typhimurium DT104 infection in Scotland, England, and Wales: January to February 2005. Commun Dis Rep CDR Wkly [serial online], 17 February 2005 [cited 2 March 2005]; 15(7): News. Available at: <http://www.hpa.org.uk/cdr/archives/2005/cdr0705.pdf>.
2.Horby PW, O'Brien SJ, Adak GK, Graham C, Hawker JI, Hunter P, et al. A national outbreak of multi-resistant Salmonella enterica serovar Typhimurium definitive phage type (DT) 104 associated with consumption of lettuce. Epidemiol Infect 2003; 130(2):169-78.
3.Ward LR, Maguire C, Hampton MD, de Pinna E, Smith HR, Little CL, et al. Collaborative investigation of an outbreak of Salmonella enterica serotype Newport in England and Wales in 2001 associated with ready-to-eat salad vegetables. Commun Dis Public Health 2002; 5(4): 301-4.
4.Sagoo SK, Little CL, Ward L, Gillespie IA, Mitchell RT. Microbiological study of ready-to-eat salad vegetables from retail establishments uncovers a national outbreak of salmonellosis. J Food Prot. 2003; 66(3): 403-9.
5.HPA. Update – Outbreak of Salmonella Newport infection in England, Scotland, and Northern Ireland: association with the consumption of lettuce. Commun Dis Rep CDR Wkly [serial online], 7 October 2005 [cited 2 March 2005]; 14(41): News. Available at: <http://www.hpa.org.uk/cdr/archives/2004/cdr4104.pdf>.
Interim guidelines on management of close community contacts of invasive group A streptococcal disease, and guidelines on the prevention of person-to-person spread of gastrointestinal infection have been published in Communicable Disease and Public Health (CDPH).
Group A streptococci cause a wide range of illnesses from non-invasive disease such as pharyngitis to more severe invasive infections such as necrotising fasciitis. There has been considerable debate about the risk of such invasive disease to close community contacts of an index case of invasive disease and whether this risk warrants antibiotic prophylaxis. Following a comprehensive literature review and preliminary analysis of 2003 United Kingdom data from the strep-EURO programme (1), the Health Protection Agency, Group A Streptococcus Working Group has published Interim UK guidelines for the management of close community contacts of invasive group A streptococcal disease (2).
The guidelines for preventing person-to-person spread following gastrointestinal infections replace those published in the CDR Review in 1995 (4). They provide concise, accessible advice to public health professionals, particularly those who do not specialise in communicable disease control.
This, the final issue of CDPH also contains papers on infection control, immunisation issues, the health of drug users, HIV, laboratory methods, and infection in the community. CDPH was created in 1998 by amalgamating the Public Health Laboratory Service’s quarterly Microbiology Digest and its four-weekly Communicable Disease Report (CDR) Review. Since the Health Protection Agency was formed in 2003, it was decided that it was no longer appropriate to sponsor a scientific peer reviewed journal exclusively dedicated to infectious disease; now only one element of the wider remit of the Health Protection Agency.
1.Schalen C. European surveillance of severe group A streptococcal disease. Eurosurveillance Weekly 2002 ;6(35).
2.Health Protection Agency Group A Streptococcus Working Group. Interim UK guidelines for the management of close community contacts of invasive group A streptococcal disease. Commun Dis Public Health 2004; 7(4): 354-61.
3.Working Group of the former PHLS Advisory Committee on Gastrointestinal Infections. Preventing person-to-person spread following gastrointestinal infections: guidelines for public health physicians and environmental health officers. Commun Dis Public Health 2004; 7(4): 362-84. Available at <http://www.hpa.org.ok/cdph/issues/CDPHvol7/No4/guidelines2_4_04.pdf>.
4.Working party of the PHLS Salmonella Committee. The prevention of human transmission of gastrointestinal infestations and bacterial intoxications. Commun Dis Rep CDR Rev 1995; 5(11): R158-72.
On 16 February 2005, the Deutsche Stiftung Organtransplantation (German Foundation for Organ Transplantation, http://www.dso.de/) reported possible rabies in three of six patients who received organs from a donor who died in late December 2004 (1). Two of the three patients who received lung and kidney transplants died after developing progressive neurological symptoms, while the third who received kidney/pancreas transplants remains in a critical condition. All three patients tested positive for rabies virus by RT-PCR (2). The remaining three organ recipients (two corneal, one liver) have not yet shown any signs of rabies. Tests on samples from these three have so far been negative for rabies. As a precaution, all contacts of the infected donor and the infected patients in Germany have received rabies immunoglobulin and started a course of rabies vaccination. A warning was posted on the European Early Warning and Response System on 18 February.
Rabies was confirmed in the donor patient post-mortem (2). There were no clinical indications that the donor was infected with rabies prior to death from cardiac arrest in hospital. The donor is thought to have acquired infection during a trip to India in October 2004.
Person-to-person transmission of rabies has only rarely been documented following organ or tissue transplantation. Rabies transmission following corneal transplantation has been recognised as public health risk for several years, (eight cases have been described in five countries) (3). The only previous reported incident of rabies transmission following solid organ transplantation (from one donor to four liver, kidney, and vascular transplant recipients) occurred in the United States (US) in 2004 (4,5).
United Kingdom guidelines state that individuals must not donate blood or tissue for 12 months (and until fully cleared by a clinician) following a known exposure to an infectious disease (6). Exposure is identified by immunisation history and/or reported contact with rabies. There is no screening test available to determine whether or not an apparently healthy individual is infected with rabies. Rabies is a clinical diagnosis that is sometimes difficult to make, especially in countries where it is rare and where clinicians are unfamiliar with the disease. Laboratory confirmation is usually made at post mortem. The possibility remains that a donor who dies from rabies, or who is incubating the disease, could have their organs used for transplantation, without the diagnosis being considered. Although rapid tests for post mortem diagnosis of rabies are becoming available (7,8), it is likely that such test would still be associated with unacceptable delays before transplantation. Accurate travel and clinical history as well as exact identification of causes of death remain essential to reduce the risk of disease transmission.
The risk of rabies in British travellers returning from rabies endemic countries is of a similar order to Germany, which is very low. Imported cases occur once every few years. Since 1900, there have been 24 reported cases of imported rabies, the most recent two cases reported between May and June 2001 (9). Only one indigenous case (of bat rabies) has occurred since 1902. The possibility that such a case of rabies could occur, where there was no clinical suspicion, and for that person’s organs to be donated is probably also similar to that in Germany, and thought to be extremely low. The rate of organ donation in UK is 12 per million/population (around 700 donors per year) (10), whereas the rate in Germany is 14 pmp (around 1220 donors per year), which is much lower than in the US (22.7) (11).
1.Hellenbrand W, Meyer C, Rasch G, Steffens I and Ammon A. Eurosurveillance weekly [serial online] 17 February 2005 [cited 24 February 2005]; 10(7). Available at: <http://www.eurosurveillance.org/ew/2005/050217.asp#1>.
2.IInformationen zu den Tollwutuebertragungen durch Spenderorgane. Epidemiologisches Bulletin 2005; 8(70).
3.Centers for Disease Control and Prevention. Human rabies prevention--United States, 1999. Recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR Morb Recomm Wkly Rep 1999; 48(RR-1) :1-21. Erratum in: MMWR Morb Mortal Wkly Rep 1999; 48(16);MMWR Morb Mortal Wkly Rep [serial online] 2000 [cited 24 February 2005]; 49 737.
4.Centres for Disease Control and Prevention. Investigation of rabies infections in organ donor and transplant recipients--Alabama, Arkansas, Oklahoma, and Texas, 2004. MMWR Morb Mortal Wkly Rep [serial online] 9 July 2004 [cited 24 February 2005]; 53(26): 586-9 .Available at: <http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5326a6.htm>.
5.Centres for Disease Control and Prevention.Update: investigation of rabies infections in organ donor and transplant recipients--Alabama, Arkansas, Oklahoma, and Texas, 2004. MMWR Morb Mortal Wkly Rep [serial online] 2004 [cited 24 February 2005]; 53:615-6.Available at: <http://www.cdc.gov/mmwr/preview/mmwrhtml/mm53d709.htm>.
6.UK Blood transfusion services [online]. Tissue donor selection guidelines. UK Blood transfusion services, undated [cited 24 February 2005].
7.Madhusudana SN, Paul JP, Abhilash VK, Suja MS. Rapid diagnosis of rabies in humans and animals by a dot blot enzyme immunoassay. Int J Infect Dis 2004; 8:339-45.
Hemachudha T, Wacharapluesadee S. Antemortem diagnosis of human rabies. Clin Infect Dis 2004; 39:1085-6.
8.PHLS. Rabies and travel. Commun Dis Rep Wkly [serial online] 1 August 2002 [cited 24 February 2005]; 12(31): Travel. Available at: <http://www.hpa.org.uk/cdr/archives/2002/cdr3102.pdf>.
9.UK Transplant (NHS) [online]. Statistics. UK Transplant (NHS): Bristol, undated [cited 24 February 2005]. Available at: <http://www.uktransplant.org.uk/ukt/statistics/statistics.jsp>.
10.United network for Organ Sharing.Richmond, Viginia, United States: (UNOS), [cited 25 February 2005]. Available at: <http://www.unos.org/>.