The fight against Covid-19 has yet to show signs of end, as there is no specific vaccine or medication yet, so understanding the SARS-CoV-2 virus is currently the best way to protect yourself from infection.
Many scientific studies have confirmed that viruses can survive on surfaces for hours, even days, so it is important to clean the body and the surrounding environment.
Research by Rajneesh Bhardwaj and Amit Agrawal, professors at IIT Bombay (Indian Institute of Technology Bombay – a public research and engineering university located in Powai, Mumbai, India) show that cThe virus-containing particles that fall onto the surface remain infectious for several days by transforming into an ultra-thin film after the water in the droplet has evaporated.
The image depicts the thin film (center) covering the same area as the water droplet (top), having the same initial radius and angle and changes only as the vertical height.
This transformation showed that more than 99.9% of the droplet liquid disappeared in a matter of minutes, but the virus remained in a protective film of the remaining liquid. The microscopic forces keep the film just a few nanometers thick from sticking to the surface and slowing evaporation.
The membrane evaporates completely at different times, depending on the material with which it is exposed. For a large splash on stainless steel it lasts about 24 hours and copper for 16 hours, but above polypropylene it lasts up to 150 hours. A smaller droplet, only 1/10 the size, remained on the glass for more than 80 hours.
These figures are based on tests performed under laboratory conditions and may be lower than in conventional environments where the factors that promote evaporation are variable heat and airflow. Professors Rajneesh Bhardwaj and Amit Agrawal used computer and physics modeling to find out how virus-containing droplets can spread disease.
In the past, they have also found that wearing a mask reduces the size of droplets containing virus-infected particles produced by coughing up to 23 times. Within the membrane, the virus that causes Covid-19 can persist for several hours and even days on hydrophobic surfaces if left undisturbed.
The membrane covers the same amount of area as the droplet, and with the same initial radius and angle, the only measurement that changes is its vertical height. Data from the study published in the journal Physics of Fluids show that the thickness of the membrane decreases gradually and during this time the viral load in the droplet and membrane is consistent.
Prof Bhardwaj added: “What surprised us most was the dry times of these nanofilm in the hourly order. It shows that the surface is not completely dry and that the nanofilm is slowly evaporating providing the necessary medium for the survival of the Covid-19 virus.
Researchers Bhardwaj and Agrawal They say that their findings suggest the virus can persist for a long time and stress the need for frequent cleaning of surfaces or contact thoroughly.
“People should disinfect frequently touched surfaces, such as doorknobs or hand-held devices, in hospitals and other areas prone to outbreaks,” Professor Agrawal said. It is advisable to clean by heating the surfaces, since a shorter time higher than the surrounding environment can also help evaporate the nanofilm and destroy the virus. “
Huong Giang (Source: dailymail)