Role of Infected Food Handlers Highlighted in Norovirus Outbreaks in Spain
Researchers have recently emphasized the role of infected food handlers in two norovirus outbreaks that occurred in Spain. The outbreaks occurred a week apart in the same facility in Lleida, Spain, in 2018, with symptoms including abdominal pain, vomiting, and nausea being the most common among the affected individuals.
The first outbreak was linked to the consumption of salad, while the second outbreak was associated with a cheese omelet. Both groups of students, as well as the food handlers who prepared the meals, were found to have been infected with norovirus, which was detected through RT-PCR and sequencing, according to a study published in the journal Scientific Reports.
The initial outbreak was reported in April 2018 when the Epidemiological Surveillance Service of Lleida, Alt Pirineu, and Aran received a report of acute gastroenteritis affecting a group of students from a high school in Lleida who had attended a holiday camp house. Just a week later, another outbreak was reported at the same facility, affecting a different group from the same school.
The first outbreak had 19 patients, with symptoms appearing two days after their arrival at the camp house. The second outbreak involved 12 cases. It was determined that there were two food handlers present at the camp house.
In the first outbreak, 26 out of 29 surveys from the group members were analyzed, and all 26 individuals had fallen ill. The affected students were aged 12 and 13, while the three teachers affected were between 43 and 53 years old.
Upon investigation, it was discovered that the source of exposure in the first outbreak was the consumption of salad. The incubation period for the 22 identified cases was calculated to have a median of 31 hours, ranging from 27 to 46 hours. Norovirus was detected in five fecal samples from the patients, although analysis of a salad sample did not yield any positive results.
It was found that the first food handler had experienced symptoms of acute gastroenteritis the day prior to the arrival of the first school group, while the second food handler developed symptoms the day after their arrival. Interestingly, fecal samples from both handlers tested negative for norovirus.
In the second outbreak, 16 out of 23 surveys were analyzed, and all 16 individuals had fallen ill. The age range of those affected remained between 12 and 13. In this outbreak, it was determined that the consumption of a cheese omelet was the source of exposure. The incubation period for the 15 patients was calculated to have a median of 28 hours, ranging from 16 to 49 hours. Norovirus was detected in four stool samples from the patients, although analysis of the omelet sample was inconclusive.
Surprisingly, in the investigation following the second outbreak, it was found that fecal samples from both food handlers tested positive for norovirus. Additionally, it was observed that sinks in the toilets and handwashing points in the kitchen were not equipped with soap dispensers and paper towels, and proper disinfectant guidelines were not being followed for cleaning surfaces. As a result, a professional cleaning company was employed to disinfect the kitchen and toilets.
To prevent further outbreaks at the same facility, the researchers suggested that food handlers with symptoms of gastroenteritis should refrain from working until 48 hours after their symptoms have resolved. Furthermore, it is crucial to ensure that appropriate handwashing mechanisms, such as soap dispensers and hand dryers, are available throughout the facility. Proper cleaning of surfaces must also be carried out in accordance with guidelines.
The findings of this study emphasize the importance of excluding food handlers with gastroenteritis from work, ensuring adequate availability of mechanisms for proper handwashing, and implementing correct cleaning procedures to prevent the recurrence of outbreaks in similar settings.
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