With at least 67 sick from Vibrio parahaemolyticus linked to raw oysters in Canada and a full recall being launched by the Canadian Food Inspection Agency, one has to wonder why raw oysters would be served in a nursing home.
Researchers report that the presence of norovirus in shellfish is a public health concern in Europe. Here, we report the results of an investigation into a norovirus gastroenteritis outbreak following a festive lunch which affected 84 (57%) residents and staff members of a nursing home in January 2012 in France. Individuals who had eaten oysters had a significantly higher risk of developing symptoms in the following 2·5 days than those who had not, the risk increasing with the amount eaten [relative risk 2·2 (1·0–4·6) and 3·3 (1·6–6·6) for 3–4 and 5–12 oysters, respectively].
In healthy individuals during those days, 29 (32%) subsequently became ill, most of whom were staff members performing activities in close contact with residents. Genogroup II noroviruses were detected in fecal samples, in a sample of uneaten oysters and in oysters from the production area. Identifying a norovirus’s infectious dose may facilitate the health-related management of contaminated shellfish.
A norovirus oyster-related outbreak in a nursing home in France, January 2012
Epidemiology and Infection / Volume 143 / Issue 12 / September 2015, pp 2486-2493
Loury, F. S. Le Guyader, J. C. Le Saux, K. Ambert-Balay, P. Parrot and B. Hubert