Norovirus, A Class of Stomach Viruses Can Spread Through Saliva


Scientists have recently discovered Norovirus, a class of stomach viruses that are known to cause severe diarrheal diseases.

These include a famous widespread outbreak that was spotted on cruise ships. It can grow on the salivary glands of the mice and has the capability to spread through saliva.


What Is Norovirus?

Norovirus happens to be a group of infecting viruses responsible to cause severe vomiting and diarrhea.

It’s also sometimes referred to stomach flu. Please note that norovirus is a highly contagious form of virus and can largely spread in humans, surfaces or infected food.


Norovirus First Spotted In Ohio

Although, the first virus was found in the year 1968 in Ohio, USA, it has quite recently made its attention in India as it affected as many as two children in Thiruvananthapuram, Kerala.

Since the virus is highly contagious, the health department officials have already alerted people about it.

The main reason why it becomes tougher to nail the norovirus is because it has different types of strains. Due to the several forms of norovirus, treatment for one type is not adequate for another type of norovirus.

The virus doesn’t cause panic among adults but has been found to cause severe issues in children and adults having low immunity levels. And so, those having a compromised immunity are mainly found to be at the risk of developing severe complication.


New Research Says Norovirus Can Spread Through Saliva

Now, as per the new findings, scientists have discovered this new class of viruses which affect billions of people annually and can even prove lethal

These viruses are generally categorized as enteric viruses and can spread through saliva which can happen through sneezing, coughing, talking or even sharing foods and utensils. The virus can also spread through kissing. But the new finding is still to be analyzed in humans.

The above finding has been published in the journal Nature. It’s believed that it can surely lead to better diagnose, prevent and treat such diseases caused by these class of viruses. The above study is led by the National Heart Lung, and Blood Institute (NHBLI).

Some forms of enteric viruses like rotaviruses and noroviruses can largely spread by eating food mixed with contamination. It can even be contaminated with fecal matter containing these viruses.

For example, enteric viruses were always thought to easily bypass the salivary glands to enter intestines. And they later exit through feces.

But now, the new research needs to be confirmed that says salivary transmission of enteric viruses is also possible in humans. If it comes out to be true in humans, then this mode of transmission will be easier and common in humans as compared to the traditional route.

For the above study, researchers chose to feed a number of newborn mice less than 10 days old with rotavirus or norovirus. After feeding them with viral doses, they were made to return to their cages. They were even allowed to suckle their virus-free mothers.

Right after one day, one of the researchers found something unusual. They spotted mouse pups a surge in igA antibodies that are well known disease fighting agents found in blood. This surprised them as they couldn’t have expected them to release antibodies at such an initial stage.

The team of researchers noticed some more unusual things. They found the viruses were replicating in the breast tissues of their mothers at somewhat higher levels. Later they found that release of antibodies in their guts mirrored the timing of the igA surge in mother’s milk.

And so, it looked as if the infection in their mother’s milk simply boosted the production of igA antibodies in their breast milk. And this actually made the infection in their pups.


Researchers Found Norovirus Replicating In Salivary Glands of Mouse Pups

At this time, researchers wanted to know how the viruses (noroviruses and rotaviruses) made their presence in the breast tissue. In order to find this out, they made some more experiments.

They found that it was not mouse pups that transmitted the virus infections to their mothers through the basic conventional route which is generally spread by leaving contaminated feces and made by their mothers to ingest.

At this time, the team of researchers wanted to see if the presence of viruses in the mother’s breast tissue have come through the saliva of the pups that were made infected. And the infection might have spread through breastfeeding.

In order to confirm this theory, they analyzed saliva and salivary glands that were found to have been replicating with the viruses and from there shedding them into the saliva.