The Kerala government, on Monday, January 23, announced that norovirus was detected in students of a school in Kakkanad. Two school students studying in class 1 and 2 were found infected, in addition to three other children who are under treatment. The health department also said that 62 students and some parents were exhibiting symptoms of the viral infection.
However, this is not the first instance of norovirus in the state. Kerala had reported norovirus cases in November 2021 and June 2022. The World Health Organisation has estimated that around 685 million norovirus cases are reported annually, including 200 million cases in children under the age of five. It is also estimated that two lakh deaths are caused every year due to the viral infection and this includes 50,000 children’s deaths.
The World Health Organisation (WHO) classifies norovirus as a viral illness that causes “acute gastroenteritis”. Acute gastroenteritis refers to inflammation of the stomach or intestines. There are multiple types of norovirus, and it is also sometimes called ‘stomach flu’ or ‘stomach bug’.
The norovirus can spread if a person has direct contact with another infected person or by touching contaminated surfaces and then making contact with the mouth. The easiest way for transmission of the virus is through contaminated food or water.
According to the US Centers for Disease Control and Prevention, symptoms to look out for include diarrhoea, vomiting, nausea, stomach pain, fever, headache, dehydration and body ache. Symptoms usually develop within 12 to 48 hours after being exposed to norovirus, and recovery happens within one to three days.
In a recent research by a team at the US National Institutes of Health (NIH), it has been found that a new route of transmission exists for norovirus - through saliva i.e. coughing, talking, sneezing, sharing food and utensils, and even kissing, all have the potential for spreading the viruses. However, this still needs to be confirmed in human studies.
The findings, which appear in the journal Nature, could lead to better ways to prevent, diagnose, and treat diseases caused by these viruses, potentially saving lives. "This is completely new territory because these viruses were thought to only grow in the intestines," said senior author Nihal Altan-Bonnet, chief of the Laboratory of Host-Pathogen Dynamics at the National Heart, Lung, and Blood Institute (NHLBI), part of the NIH.
"Salivary transmission of enteric viruses is another layer of transmission we didn't know about. It is an entirely new way of thinking about how these viruses can transmit, how they can be diagnosed, and, most importantly, how their spread might be mitigated," Altan-Bonnet said. Researchers have known for some time that enteric viruses, such as norovirus and rotavirus, can spread by eating food or drinking liquids contaminated with faecal matter containing these viruses. Enteric viruses were thought to bypass the salivary gland and target the intestines, exiting later through faeces. For the study, the researchers fed a group of newborn mice, which were less than 10 days old, with either norovirus or rotavirus.
One of the ways to prevent transmission is by washing hands thoroughly with soap and water before eating, handling food, and cooking. One should also boil water before using it for drinking or cooking purposes and avoid consuming food or water that has been kept without proper hygiene.
(With IANS inputs)