The Azores Regional Health Authority (ARS) confirmed on Monday that norovirus is responsible for a rise in acute gastroenteritis cases on São Miguel, the largest island in the Portuguese archipelago, but said the situation "does not constitute cause for alarm."
In a statement, the ARS said the confirmation followed the epidemiological situation recently observed on the island of Faial and an increase in acute gastroenteritis cases on São Miguel. Laboratory analysis of biological samples from registered cases on the island confirmed the presence of norovirus, the authority said.
The ARS said available data continue to show that the large majority of cases present a mild, self-limited clinical picture, characterized mainly by diarrhea and/or vomiting, with most people recovering spontaneously after a few days.
How norovirus spreads
The laboratory identification of norovirus is consistent with this clinical pattern and reinforces the need for prevention measures already underway, the ARS said, given the virus's high transmissibility through the fecal-oral route, contact with contaminated surfaces and, occasionally, food or water. Norovirus is a common cause of acute gastroenteritis outbreaks worldwide, particularly in settings such as care homes, schools and food establishments, because of how easily it spreads between people and via contaminated surfaces.
The ARS said there is currently "no evidence" linking the cases to the public water supply network. Even so, preventive coordination continues with the entities that manage water supply systems, along with "rigorous monitoring" of water quality and other potential factors of exposure.
Epidemiological and laboratory investigation is continuing, including testing for other intestinal pathogens, the authority said.
Daily monitoring under way
The situation is being monitored daily by the ARS, the Regional Public Health Coordination office, the health delegates of the islands involved and the Regional Health Directorate, working closely with health units, social institutions, municipalities and other entities.
The ARS said the confirmation of norovirus on São Miguel does not change the predominantly mild character of the illness, but reinforces the importance of hygiene measures and the temporary isolation of people showing symptoms. The current moment requires vigilance, prudence and collaboration, the authority said, but does not amount to cause for alarm.
Early and consistent adoption of simple prevention measures remains the most effective way to limit transmission and protect the most vulnerable people, the ARS added.
Surveillance and protective measures
The ARS said daily surveillance mechanisms remain active in emergency departments and health units across the islands, with continuous tracking of how case numbers evolve, their geographic distribution and any family or institutional clusters that may emerge.
Laboratory sample collection and targeted epidemiological investigations are also continuing, aimed at identifying common exposure factors and adjusting public health measures as needed.
Because of the situation, reinforced infection prevention and control measures have been ordered in residential facilities for elderly people, daycare centers, schools and other community institutions. The ARS said it is essential to strengthen hand hygiene and the cleaning and disinfection of frequently touched surfaces, along with active monitoring for symptoms among residents, children, service users and staff.
Restaurants, cafes and similar establishments have also been alerted to reinforce compliance with good hygiene and food safety practices.
The ARS advised the public to wash their hands frequently with soap and water, step up cleaning and disinfection of frequently touched surfaces such as bathrooms, door handles, light switches and mobile phones, and to stay at home whenever they have symptoms of diarrhea or vomiting.
