BACKGROUND: The aim of this study was to conduct an investigation into an outbreak of waterborne disease caused by Norovirus due to the consumption of contaminated drinking water. METHODS: The first week after the school summer holidays we detected an outbreak of gastroenteritis at a school in Borges Blanques (Lleida, Spain). A retrospective cohort study was carried out to investigate: water consumption and food (six items). We assessed RNA Norovirus by RT-PCR in 6 stool samples. The risk of gastroenteritis was assessed by applying adjusted risk ratio (RRa) analysis at 95% confidence intervals (CI). RESULTS: The overall attack rate was 45% (96/213). The main symptoms were: abdominal pain, 88.4% (84/95); nausea, 65.9% (62/94), and vomiting, 64.6% (62/96). The consumption of school drinking water was statistically associated with the disease (RRa: 2.8; 95% CI: 1.3-6.2). The school water tank was dirty, but this drinking water was qualified as potable. Six stool samples gave positive results for Norovirus. CONCLUSIONS: Norovirus caused this waterborne outbreak of gastroenteritis transmitted through treated drinking water. It should be obligatory to regularly clean school drinking water deposit tanks, especially after the summer holidays.
BACKGROUND: The aim of this study was to conduct an investigation into an outbreak of waterborne disease caused by Norovirus due to the consumption of contaminated drinking water. METHODS: The first week after the school summer holidays we detected an outbreak of gastroenteritis at a school in Borges Blanques (Lleida, Spain). A retrospective cohort study was carried out to investigate: water consumption and food (six items). We assessed RNA Norovirus by RT-PCR in 6 stool samples. The risk of gastroenteritis was assessed by applying adjusted risk ratio (RRa) analysis at 95% confidence intervals (CI). RESULTS: The overall attack rate was 45% (96/213). The main symptoms were: abdominal pain, 88.4% (84/95); nausea, 65.9% (62/94), and vomiting, 64.6% (62/96). The consumption of school drinking water was statistically associated with the disease (RRa: 2.8; 95% CI: 1.3-6.2). The school water tank was dirty, but this drinking water was qualified as potable. Six stool samples gave positive results for Norovirus. CONCLUSIONS: Norovirus caused this waterborne outbreak of gastroenteritis transmitted through treated drinking water. It should be obligatory to regularly clean school drinking water deposit tanks, especially after the summer holidays.
Authors: Camille Jacqueline; Manuel Del Valle Arrojo; Paloma Bellver Moreira; Maria Asunción Rodríguez Feijóo; Maria Cabrerizo; Maria Dolores Fernandez-Garcia Journal: Microbiol Spectr Date: 2022-07-14