The Kerala Health Department has confirmed two cases of the gastrointestinal infection norovirus in class 1 students in Ernakulam district.


What is norovirus?

  • Noro is a group of viruses that cause abdominal illness. It is a highly contagious virus.
    • A virus is an infectious microbe consisting of a segment of nucleic acid (either DNA or RNA) surrounded by a protein coat.
    • A virus cannot replicate alone; instead, it must infect cells and use components of the host cell to make copies of itself.
    • Often, a virus ends up killing the host cell in the process, causing damage to the host organism.
  • It is also nicknamed the “winter vomiting bug“.
    • The virus is capable of surviving low temperatures, and outbreaks tend to be more common during the winter and in colder countries.
  • The human norovirus was earlier known as Norwalk virus as it was first identified in the stool samples collected during an outbreak in Norwalk.
  • While there is no particular medication to cure norovirus infection, cleanliness is the only way one can avoid it.


Symptoms of Norovirus infection

  • Vomiting is the main classic symptom of Norovirus infection.
  • Other symptoms of the infection are nausea, diarrhoea, fever, abdominal cramps, and lethargy.
  • In children, it also causes dehydration. Dehydration in kids will lead to decrease in urination, dry mouth and throat and feeling dizzy even when standing for a few minutes.
  • According to the US CDC (Centers for Disease Control and Prevention), norovirus can cause stomach and intestine inflammation.
  • The symptoms usually last for 1 or 2 days and the patient recovers within one to three days.
    • This infection is rarely serious but if not checked at the right time it can spread fast.


Transmission –

  • Unclean and contaminated food and water are the carriers of the norovirus. The virus mainly spreads through the faecal-oral route.
  • The infection spreads either by direct consumption of infected food or else when food is served or prepared by an infected person.
  • Good hand hygiene is the best way to prevent infection. Washing hands is considered effective while hands sanitisers are thought to not work too well against norovirus.
  • As the infection can be transmitted by foods, it is suggested that a sick person not prepare food for others.
  • All food items should be carefully washed and cooked at high temperatures. Norovirus can survive in temperature up to 60°C.


How common are the norovirus infections?

  • Norovirus is not new; it has been circulating among humans for over 50 years and is thought to be one of the primary causes of gastroenteritis.
  • The virus is estimated to kill 200,000 persons globally every year, with most deaths occurring among those below the age of five years and those over the age of 65 years.
  • A 2022 study says that norovirus infections are more frequently detected in high income countries, with almost 40% cases being seen in long-term care facilities.


What is the incidence of infection in India?

  • Cases of norovirus are not as common in India as in many other places.
  • The infection has been reported in previous years as well, mainly from Southern India, and especially from Kerala.
  • In recent years, the reported cases of norovirus have been on the rise.
    • One of the reasons could well be that hospitals in India were not looking for the virus previously.
    • Now the healthcare systems have developed capabilities to detect not just this virus but several others.