What is NoV and how does it spread?
- Norovirus, which infects people across age groups, is a bug similar to the diarrhoea-inducing rotavirus.
- NoV is a highly contagious virus.
- Norovirus causes inflammation of the stomach or intestines. This is called acute gastroenteritis which is an important cause of concern in children as well as adults worldwide.
- Norovirus is sometimes called the stomach flu or stomach bug.
- Disease outbreaks typically occur aboard cruise ships, in nursing homes, dormitories, and other closed spaces.
- The initial symptoms of Norovirus are vomiting and/or diarrhoea.
- Patients also feel nauseous, and suffer from abdominal pain, fever, headaches and body aches.
- In extreme cases, loss of fluids could lead to dehydration.
- A person usually develops symptoms 12 to 48 hours after being exposed to norovirus.
- NoV transmission occurs predominantly by the faecal-oral route, directly or indirectly, through the ingestion of contaminated water or food or surfaces which might have been contaminated when handled carelessly by an infected person or his care-giver.
- There is no specific treatment and vaccine available.
- Most individuals who are not very young, very old, or malnourished can ride it out with sufficient rest and hydration.
- More care is needed if very young children, elderly or pregnant women are infected.
How common is Norovirus Infection?
- The virus was first discovered in connection with an outbreak of acute diarrhoeal disease in Norwalk, Ohio, in 1968 and was called the Norwalk Virus.
- The US Centers for Disease Control and Prevention estimates that about one out of every five cases of acute gastroenteritis worldwide is caused by Norovirus.
- Eg: According to the Centers for Disease Control and Prevention (CDC), over 20 million cases of acute diarrhoeal disease caused by NoV are reported annually in the U.S, a chunk of which are food-borne infections.
- There are 685 million cases annually, of which 200 million are detected among children younger than five years. Nearly 50,000 children die every year due to diarrhoea caused by the virus.
- In southern India, norovirus infection rates of about 10% and 44.4% were reported in two different studies during 2005-06 while a birth cohort study found that about 11.2% of diarrhoeal episodes were attributable to NoV.
How can Norovirus be Prevented?
- Prevention is rooted in hygiene.
- People should wash their hands thoroughly with soap and water before eating and after using the toilet.
- Fruits and vegetables should be thoroughly washed before eating.
- Shellfish like oysters, which might have been grown in contaminated waters, should be well-cooked.
- Boiled and safe drinking water alone should be used.
- Infected persons should rest at home and maintain utmost personal hygiene to prevent transmission.
- During outbreaks, surfaces must be disinfected with a solution of hypochlorite at 5,000 parts per million.
What makes NoV infections a public health concern?
- The transmission occurs at a rapid pace because of heavy viral shedding by the infected person.
- Even the lowest infectious dose is enough to set off extensive outbreaks, typically in environments such as hostels, schools, hospitals or nursing homes.
- Experts also point out that NoV could increasingly become a public health concern because of rapid expansion of the food industry.
Why in news?
- An acute diarrhoeal disease outbreak was reported amongst students of the College of Veterinary Sciences at Pookode, near Vythiri in Wayanad district, which were confirmed as Norovirus (NoV) by the authorities.
- These students were staying in hostels outside the campus and four out of the seven samples sent to the unit of National Institute of Virology, Alappuzha had tested positive for NoV.
- The first documented NoV outbreak in Kerala was in Alappuzha district this year between June and August when 950 cases of acute diarrhoeal disease, mostly in children, were reported from the municipal area and the nearby panchayats.