What is norovirus and what should you do to avoid catching it?

The disease spreads through contact and via contaminated food or water

water-handwashing-hand-washing-cleaning-bacteria-handwashing-shut Representational image | Shutterstock

With 34 norovirus infections reported at a veterinary college in Wayanad, Kerala’s health minister Veena George has urged people to be vigilant.

“With proper prevention and treatment, the disease can be cured quickly. Therefore, everyone should be aware of the disease and its means of prevention,” George said.

Symptoms of norovirus include diarrhoea, vomiting, nausea and stomach pain. The symptoms may result in severe dehydration.

Treatment includes taking rest, consuming oral rehydration salts (ORS) and possible further medical care if needed.

With Kerala recently reporting a case of Nipah (in September), Zika (over 70 cases in July) and a continuing ebb of COVID-19 cases (over 6,600 cases as of Friday), the addition of a new virus to worry about may be concerning. However, norovirus, while contagious, is seldom fatal in adults.

“A systematic review of 39 studies in adults aged > 65 years worldwide reported the hospitalization rate for norovirus gastroenteritis as 1–19 per 10,000 persons and the mortality rate as 0.4–3.2 per 100,000 persons,” stated a 2019 review published in BMC Infectious Diseases.

Usually transmitted via contaminated food or water, or by touching contaminated surfaces and then touching one’s mouth with unwashed hands, or via direct contact with an infected person, norovirus is the leading cause of acute gastroenteritis, annually causing an estimated 685 million cases, according tot the US Centres for Disease Control (CDC). “About 200 million cases are seen among children under 5 years old, leading to an estimated 50,000 child deaths every year, mostly in developing countries,” the CDC says.

“It only takes a very small amount of norovirus particles (fewer than 100) to make you sick. People with norovirus illness shed billions of virus particles in their stool and vomit and can easily infect others,” the CDC says, noting that the virus can spread quickly in enclosed places like daycare centers, nursing homes, schools, and cruise ships. Norovirus can also stay on objects and surfaces and still infect people for days or weeks. It can also survive some disinfectants, making it hard to get rid of.

With all the cases reported coming from a single college, the Kerala health ministry has stepped in to sanitise the water supply with super chlorination of water, according to the health minister.

“Drinking water sources need to be ensured to be hygienic," she said.

The national guidelines for prevention of gastrointestinal infections in hospital wards recommend hand hygiene, use of personal protective equipment, following asyptic techniques, cleaning and decontaminating soiled instruments followed by sterilisation or high-level disinfection, appropriate disposal of biomedical waste (BMW), appropriate cleaning and disinfection of the environment, improving safety in operating rooms and other high-risk areas and maintaining a safe working environment and safe work practice.

The CDC recommends practising proper hand hygiene, washing fruits and vegetables and cooking seafood thoroughly, avoiding preparing food or caring for others when you are sick, cleaning and disinfecting contaminated surfaces and washing laundry thoroughly.