Human Listeriosis, England, 1999–2009 | CDC EID

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Volume 17, Number 1–January 2011
Research
Concurrent Conditions and Human Listeriosis, England, 1999–2009

Piers Mook, Comments to Author Sarah J. O'Brien, and Iain A. Gillespie

Author affiliations: Health Protection Agency, London, UK (P. Mook, I.A. Gillespie); and University of Manchester, Manchester, UK (S.J. O'Brien, I.A. Gillespie)

Suggested citation for this article

Abstract
The epidemiology of listeriosis in England and Wales changed during 2001–2008; more patients >60 years of age had bacteremia than in previous years. To investigate these changes, we calculated risk for listeriosis by concurrent condition for non–pregnancy-associated listeriosis cases reported to the national surveillance system in England during 1999–2009. Conditions occurring with L. monocytogenes infection were coded according to the International Classification of Diseases, 10th Revision, and compared with appropriate hospital episode statistics inpatient denominator data to calculate incidence rates/million consultations. Malignancies (especially of the blood), kidney disease, liver disease, diabetes, alcoholism, and age >60 years were associated with an increased risk for listeriosis. Physicians should consider a diagnosis of listeriosis when treating patients who have concurrent conditions. Providing cancer patients, who accounted for one third of cases, with food safety information might help limit additional cases.

Listeriosis is a rare but serious foodborne disease caused by the bacterium Listeria monocytogenes. Three groups of persons are disproportionately affected: the elderly, the immunocompromised, and pregnant women and their unborn or newborn infants. The clinical signs of disease in these persons include septicemia, meningitis, and miscarriage. Pregnant women can transmit the infection to the fetus, for whom the result can be deadly. However, these women may not have clearly overt signs or symptoms of infection. Case-fatality rates range from 20% to 50% (1). The susceptibility of healthy persons to symptomatic listeriosis is substantially less than that of persons with underlying conditions.

Persons with cancer, diabetes, AIDS, and liver or kidney disease are often predisposed to severe infection and death after infection with L. monocytogenes. This predisposition is a consequence of suppressed T-cell–mediated immunity (2) caused by the condition or its treatment. Similarly, pregnant women, the elderly, and those receiving immunosuppressive therapy are also at risk because of impaired or modulated immune function.

The epidemiology of listeriosis in England and Wales has changed since 2001 (3). Incidence has increased (2.1 cases/million population during 1990–2000 vs. 3.6 cases/million population during 2001–2009), and more cases have been found in persons >60 years of age who had bacteremia (but not meningitis). Similar patterns have been reported in other countries in Europe (4–6). The reasons for these changes are not fully understood, but they do not seem to be caused by surveillance artifacts and are not associated with sex, season, geography, ethnic or socioeconomic differences, underlying conditions, or L. monocytogenes subtype (3). We have showed that the increase occurred in persons with cancer or other conditions whose treatment included acid-suppressing medication (7). In view of recent trends, we examined national surveillance data for England to quantify the role of concurrent conditions in persons with listeriosis and stratified these conditions to examine risks for persons >60 years of age.

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Human Listeriosis, England, 1999–2009 | CDC EID

Suggested Citation for this Article

Mook P, O'Brien SJ, Gillespie IA. Concurrent conditions and human listeriosis, England and Wales, 1999–2009. Emerg Infect Dis [serial on the Internet]. 2011 Jan [date cited]. http://www.cdc.gov/EID/content/17/1/38.htm

DOI: 10.3201/eid1701.101174

Comments to the Authors

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Piers Mook, Gastrointestinal, Emerging and Zoonotic Infections Department, Centre for Infections, Health Protection Agency, 61 Colindale Ave, London NW9 5EQ, UK; email: piers.mook@hpa.org.uk