Ahead of Print -Salmonella enterica Serovar Enteritidis, England and Wales, 1945–2011 - Volume 20, Number 7—July 2014 - Emerging Infectious Disease journal - CDC
Volume 20, Number 7—July 2014
Salmonella enterica Serovar Enteritidis, England and Wales, 1945–2011
Christopher R. Lane, Susan LeBaigue, Oluwaseun B. Esan, Adedoyin A. Awofisyo, Natalie L. Adams, Ian S.T. Fisher, Kathie A. Grant, Tansy M. Peters, Lesley Larkin, Robert H. Davies, and Goutam K. Adak
Author affiliations: Public Health England, London, UK (C.R. Lane, S. LeBaigue, O.B. Esan, A.A. Awofisayo, N.L. Adams, I.S.T. Fisher, K.A. Grant, T.M. Peters, G.K. Adak); Animal Health and Veterinary Laboratories Agency, London (L. Larkin, R.H. Davies)
A pandemic of Salmonella enterica serovar Enteritidis infection was recognized by epidemiologists in the United States in the late 1970s; a 6-fold rise in these infections was observed in northeastern United States during 1976–1986 (1). A review of outbreak investigations revealed that 27 (77%) of 35 outbreaks were associated with the consumption of foods containing grade A eggs (1). The most commonly reported phage types were SE8, SE13, and SE13a. In 1990, the World Health Organization reviewed Salmonella surveillance data for 1979–1987 and found that isolation rates for S. enterica ser. Enteritidis had increased in 24 of the 35 nations that provided data. Increases were recorded in countries from every continent except Asia (2). Evidence from outbreak investigations in Spain, Hungary, France, Norway, and the United States implicated eggs (3). Microbiologicical investigations conducted in the United Kingdom also showed the presence of phage type SE4 in chicken meat (4) and raw shell eggs (5,6). In 1988, the UK Public Health Laboratory Service Communicable Disease Surveillance Centre conducted a case–control study of primary sporadic SE4 infections in England. The investigators demonstrated associations between human infection and the consumption of chicken and raw egg dishes (7). We reviewed national surveillance and research data to examine the factors underlying the epidemic of S. enterica ser. Enteritidis and to estimate its overall impact on the population of England and Wales.
Surveillance of S. enterica Infections and Other Intestinal Diseases in England and Wales
Systematic national surveillance of laboratory-confirmed salmonellosis in humans in England and Wales has been in continuous operation since 1945. Diagnostic laboratories refer all Salmonellaisolates to the national reference laboratory for confirmation and characterization, and data on all first confirmations are entered into a national surveillance database (8).
We extracted data from this database to provide annual totals for human infection with S. enterica by serotype and phage type. Multipliers derived from previous studies (9–11) were applied to the number of laboratory reports received to produce estimates of the numbers of community cases, days of illness, hospitalizations, hospital bed-days occupied, and deaths for 1982–1987, 1988–1998, and 1999–2011 that were attributable to SE4. Multipliers published in 1996 (9) were used for the emergence and epidemic stages and those from 2008 (10) for the decline stage.
In addition, local health protection units return standardized data (i.e., etiology, outbreak location, morbidity/mortality rates, vehicles of infection, and evidence of association) on all detected general outbreaks of infectious intestinal diseases to national surveillance (12). These data are also stored in a dedicated database.
Surveillance of S. enterica in Poultry
Data on Salmonella spp. in poultry in Great Britain (England, Wales, and Scotland) are reported by the Animal Health and Veterinary Laboratory Agency (13). A Salmonella incident is defined as the first isolation of a given serovar from a particular animal, group of animals, or their environment on a single premises within a defined period (usually 30 days) (13).
Data were abstracted from the national surveillance databases described above. Descriptive analyses were done in Microsoft Excel 2007 (Microsoft Corporation, Redmond, WA, USA); 95% CIs of the estimates of the burden of disease in the community were calculated from the upper and lower confidence limits reported in previous studies (9,10). All statistical analyses were performed by using Stata version 12 (StataCorp LP, College Station, TX, USA).
Mr Lane is an epidemiologist at Public Health England in London. He works in gastrointestinal disease surveillance, mainly focusing on the epidemiology of salmonellosis.
We thank the microbiologists, health protection, and environmental health specialists that have contributed data and reports to national surveillance systems and the epidemiologists and information officers who have worked on the national surveillance of intestinal infectious diseases for Centre for Infectious Disease Surveillance and Control and Health Protection Services Colindale.
- Figure 1. Laboratory reporting of Salmonella enterica infections in England and Wales, 1945–2011Emergence stage, 1982–1987; epidemic stage, 1988–1998; decline stage, 1999–2011Ser., serovar.
- Figure 2. Laboratory reporting of indigenously acquired Salmonella enterica serovar Enteritidis infections in England and Wales, 1982–2011Emergence stage, 1982–1987; epidemic stage, 1988–1998; decline stage, 1999–2011SE4, S. enterica serEnteritidis phage type 4....
- Figure 3. Trends in the pathogens associated with general outbreaks of foodborne infection in England and Wales, 1992–2011SE4, Salmonella enterica serovar Enteritidis phage type 4.
- Figure 4. Trends in the reporting of general outbreaks of salmonellosis associated with the consumption of eggs in England and Wales 1992–2011SE4, Salmonella enterica serovar Enteritidis phage type 4.
- Figure 5. Trends in the reporting of incidents of Salmonella enterica in chickens in Great Britain versus laboratory reporting of human S. enterica serovar Enteritidis infection, England and Wales, 1985–2011SE4, S....
- Figure 6. Trends in reporting of Salmonella enterica serovar Enteritidis phage type 4 (SE4), extrapolated burden of disease, and estimated number of cases prevented by SE4 elimination programs, England and Wales,...
- Table. Estimated rates of disease attributable to Salmonella enterica serovar Enteritidis phage type 4 during 3 periods, England and Wales, 1982–2011
Suggested citation for this article: Lane CR, LeBaigue S, Esan OB, Awofisyo AA, Adams NL, Fisher, IST. Salmonella enterica serovar Enteritidis, England and Wales, 1945–2011. Emerg Infect Dis [Internet]. 2014 Jul [date cited]. http://dx.doi.org/10.3201/eid2007.121850