Coronavirus: why saying words with "p" and "t" raises the risk of contagion

10/21/2020 6:00 AM

• Clarín.com

• Society

Updated 10/21/2020 6:00 AM

Droplets of saliva are contagious.

That is one of the knowledge that we incorporate (by force) in this 2020 marked by the coronavirus pandemic.

By kissing, coughing or sneezing, an infected person can spread Covid-19.

You can also do it 

: that is why it is said and repeated that it is important to wear a mask and maintain social distancing.

A simple chat with a family member or friend -of not complying with these prevention measures- is a risky situation if one of the two is infected and does not know it.

What is still little known is how these droplets of saliva are produced that we all inadvertently send out in aerosol form.

Now a new study has advanced on this topic and detected the mechanism by which

.

The research was conducted by scientists Manouk Abkarian;

from the University of Montpellier, France: and Howard Stone, from the University of Princeton, United States.

Their results were published in the journal Physics.

"Speech is a powerful route for viral transmission in the Covid-19 pandemic. It is difficult to develop well-founded mitigation strategies since no aerosolization mechanism has yet been visualized in the oral cavity," the authors describe in their study. .

What Abkarian and Stone did was record with a high-speed camera a volunteer - a 44-year-old French man - and asked him to speak a series of words.

In one of the research videos, for example, the person pronounces the syllable "pa" and the footage shows how a film of saliva forms between the lips, which then separates into a series of strands that remain under tension.

Due to the force of the air, in thousandths of seconds droplets break off and break into a line.

This process, the authors say,

- those in which sound is produced by obstructing and then releasing airflow - which are used in 95% of the world's most widely spoken languages.

In all of them there is this passage of a blast of air through a space with these filaments of saliva.

The same does not happen, for example, with the consonant "m" since much of the air

.

For the researchers, 

- a property of saliva - is essential because it allows these filaments to stretch while receiving the air that blows through the lips.

In practice, it is the way in which they "gain momentum" to break up into droplets and make them fly away.

Another finding from the study may lead to new methods to reduce the spread of Covid-19.

In the case studied, it was found that the use of lip balm

the number of droplets sprayed when speaking by

.

"Our research suggests a mitigation of droplet production during speech by using a lip balm," they stated in their conclusions.

They also raised some questions as a trigger for the development of new research.

Among others, if there are languages ​​more prone to spreading saliva, if the age of the person influences and if the virus itself may be inducing modifications in the saliva of the carriers to promote aerosolization.

For now, they could not offer answers.

DD