Like every winter, norovirus made a comeback a few weeks ago. This year, they are back in force. Last December, the United States reported that the number of cases of infection had already doubled in the country compared to the same period in 2023. But what, really, is a norovirus? Here are four points to help you see clearly.
Noroviruses are the most common cause of nonbacterial gastroenteritis, often called “stomach flu.” They take their name from the town of Norwalk, Ohio (United States), where they were identified after a gastro outbreak in a school in 1968. Extremely infectious – 10 to 100 viruses are enough to cause a contamination, according to the Federal Office of Public Health (FOPH) -, noroviruses owe their high contagiousness to their ability to mutate and survive in water and on surfaces (up to twelve days!).
Generally, symptoms appear between twelve and forty-eight hours after infection, in the form of stomach aches, projectile vomiting or severe diarrhea. They can also be accompanied by headaches, muscle pain, possibly fever and weakness. These symptoms usually disappear spontaneously after two or three days, except in certain patients.
-In Switzerland, 400,000 people are affected each year, according to the OFSP. They are infected through the mouth (by swallowing contaminated drinks or food), the nose (by inhaling airborne droplets) or by contact (dirty hands, contaminated surfaces). Present throughout the world and all year round, with a preponderance in winter, noroviruses often multiply in community settings: hospitals, schools, daycares, barracks or cruise ships. Protection comes first and foremost through prevention: barrier gestures, hand washing, wearing a mask.
There is no treatment or vaccine. Doctors recommend drinking enough to compensate for fluid loss and avoid dehydration. Norovirus gastroenteritis can, however, cause complications – acute renal failure, electrolyte disturbances – even in healthy patients, recalls the “Swiss Medical Review”. Immunosuppressed people also have a high risk of developing chronic gastroenteritis. The medical literature also mentions fatal cases.
