A norovirus outbreak hit the picturesque village of Torri del Benaco on the shores of Lake Garda, Italy, last week.
More than 300 people have sought medical treatment for the highly contagious stomach bug. The virus is known for its sudden onset of gastrointestinal symptoms such as diarrhea, vomiting, stomach cramps and fever.
The rapid spread of the illness led to an immediate investigation by health authorities, who confirmed the presence of the highly contagious norovirus in stool samples of affected individuals.
It's not yet clear what caused the sudden norovirus outbreak, but local health experts suspect the local water supply. Authorities have issued warnings for people in the area not to drink the tap water.
Italian newspapers reported that the outbreak was likely linked to an overload of the sewage system due to unusually high water levels in Lake Garda after heavy rains in recent weeks.
Local authorities are investigating the potential causes, and have added chlorine to the water network to disinfect the local water supply.
What causes norovirus infection?
Norovirus is primarily spread person-to-person through the fecal-oral route, meaning it's transmitted by ingesting tiny particles of infected fecal matter or vomit.
This can happen through direct contact with an infected person, consuming contaminated food or water or touching contaminated surfaces, and then touching your mouth.
The virus is also remarkably resilient and can survive on surfaces for days, making it easy to spread in places like unsanitary food preparation settings.
Contaminated foods like leafy greens and shellfish are commonly associated with norovirus outbreaks.
How dangerous is norovirus?
It's unusual for norovirus to cause serious symptoms — infection is usually short-lived, with symptoms disappearing after half a day to two days.
However, dehydration can be a risk factor, especially for children, elderly adults and those with other health problems or with weakened immune systems.
There is no treatment, so the best you can do is let the virus run its course and try to prevent people around you from getting ill.
Symptoms like severe dehydration, persistent vomiting and diarrhea, or symptoms lasting more than a few days, require medical attention.
How to prevent the spread of norovirus
Exposure to as little as 20 norovirus particles can cause an infection, meaning even the slightest trace of contaminated matter can cause the illness to spread quickly.
But if you use strict hygiene practices, the spread of norovirus can be prevented. Here are some key measures:
Hand hygiene: Wash hands thoroughly with soap and water, especially after using the toilet and before eating or preparing food. Alcohol-based hand sanitizers are less effective against norovirus.
Food safety: Ensure food is cooked properly, and avoid consuming raw or undercooked shellfish, which can be a source of the virus.
Cleaning and disinfection: Clean and disinfect surfaces regularly, especially in communal areas. Use bleach-based cleaners, as norovirus is resistant to many other disinfectants.
Isolation: If you or a family member is infected, avoid contact with others as much as possible until 48 hours after symptoms subside.