Norovirus in Bottled Water Associated with Gastroenteritis Outbreak, Spain, 2016

In April 2016, an outbreak of gastrointestinal illness (4,136 cases) occurred in Catalonia, Spain.We detected high levels of norovirus genogroups I and II in office water coolers associated with the outbreak.Infectious viral titer estimates were 33-49 genome copies/L for genogroup I and 327-660 genome copies/L for genogroup II.D uring April 11-25, 2016, a total of 4,136 cases of gas- troenteritis were reported by the Public Health Agency of Catalonia (ASPCAT; Figure , panel A).A case-patient was defined as an exposed person who had vomiting or diarrhea (3 or more loose stools within 24 hours) and >2 of the following: nausea, abdominal pain, or fever (≥37.8°C).Six patients required hospitalization.The epidemiologic investigation conducted by the ASPCAT pointed toward an association of the outbreak with drinking bottled spring water from office water coolers; the water had been bottled at a source in Andorra (M.Jané-Checa and A. Martínez-Mateo, Public Health Agency of Catalonia, pers.comm., 2016 Sep 1).Compared with other modes of transmission such as food or person to person, norovirus outbreaks associated with drinking water are rare in developed countries (1).On April 15, 2016, as a precautionary measure, the company producing the bottled water recalled >6,150 containers of water of suspected quality that had already been distributed to 925 companies.The water complied with all requirements of the European Commission directive on the exploitation and marketing of natural mineral waters (2), but these requirements do not include any virologic determination.The Spanish Authority for Consumption, Food Safety, and Nutrition reported the outbreak at the national (http://www.aecosan.msssi.gob.es/AECOSAN/web/se-guridad_alimentaria/ampliacion/gastroenteritis_agua_envasada.htm) and European (Rapid Alert System for Food and Feed, RASFF, expedient 2017/0469, https://webgate.