Officials have revealed findings from an investigation after hundreds of people reported feeling sick after going to a celebration in the town of Berkel en Rodenrijs.

GGD Rotterdam-Rijnmond and NVWA looked into the source of illnesses. The biggest cause of gastrointestinal complaints appeared to be norovirus. A total of 918 people reported being sick after attending the event but no serious illnesses were recorded.

GGD Rotterdam-Rijnmond visited the site where King’s Day was celebrated in Berkel en Rodenrijs several times and stool samples from 11 people were examined in the laboratory.

Based on a digital questionnaire, which was partially completed by 2,680 respondents, 900 people reported being sick. Analysis showed that people who had drunk something from the stall of one café or in the café itself became ill more often. This applied to alcoholic and non-alcoholic drinks and there was no link with food.

An employee at the café became ill while working on King’s Day and was likely able to infect other people. The café followed the catering code by sending the sick person home as soon as symptoms became clear, but the virus was able to spread in the meantime. An NVWA inspection found no violations.

Officials said there are indications that norovirus was circulating in Berkel en Rodenrijs before King’s Day. Three of the 11 people with a positive norovirus result had the same type of the virus as the employee through genetic testing. They added it is likely that not everyone who became ill was infected from the same source.

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