Epidemiology and Infection



A community-wide outbreak of Salmonella enterica serotype Typhimurium infection associated with eating a raw milk soft cheese in France


H. DE VALK a1a2c1, E. DELAROCQUE-ASTAGNEAU a1, G. COLOMB a3, S. PLE a4, E. GODARD a3, V. VAILLANT a1, S. HAEGHEBAERT a1, PH. BOUVET a5, F. GRIMONT a6, P. GRIMONT a5a6 and J.-C. DESENCLOS a1
a1 Institut de Veille Sanitaire, Saint-Maurice
a2 European Programme For Intervention Epidemiology Training
a3 Direction Départementale des Affaires Sanitaires et Sociales, Lons-le-Saunier
a4 Direction Départementale des Services Vétérinaires, Lons-le-Saunier
a5 Centre National de Référence des Salmonella et des Shigella, Insititut Pasteur, Paris
a6 Centre National de Référence du Typage Moléculaire Entérique, Institut Pasteur, Paris

Abstract

In 1997, a community-wide outbreak of Salmonella enterica serotype Typhimurium (S. typhimurium) infection occurred in France. The investigation included case searching and a case-control study. A case was defined as a resident of the Jura district with fever or diarrhoea between 12 May and 8 July 1997, from whom S. typhimurium was isolated in stool or blood. One hundred and thirteen cases were identified. Thirty-three (83%) of 40 cases but only 23 (55%) of 42 community controls, matched for age and area of residence, reported eating Morbier cheese (Odds ratio: 6·5; 95% Confidence Interval: 1·4–28·8). Morbier cheese samples taken from the refrigerators of two case-patients and one symptom-free neighbour cultured positive for S. typhimurium of the same phage type as the human isolates. The analysis of distribution channels incriminated one batch from a single processing plant. These findings show that an unpasteurized soft cheese is an effective vehicle of S. typhimurium transmission.


Correspondence:
c1 Author for correspondence: Institut de Veille Sanitaire, 12 rue du Val d'Osne, 94415 St Maurice cedex, France.


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