The SARS-CoV-2 “body” measures approximately 100 nanometers, that is, 10,000 times less than a millimeter, which is a similar ratio to comparing a centimeter ant with a length of 100 meters. We know that this tiny virus attacks the lungs, and that attaches to hair-like extensions known as cilia, which are found in some cells that line the respiratory system. These cilia are usually between six and seven micrometers long, that is, tens of times larger than viruses. With these dimensions in mind, it is perhaps more interesting to ask the following: how does SARS-CoV-2 invade these cells?
There are already many images that exist that show how this invasion occurs, but this week a group of scientists from the University of North Carolina (USA) has published a new snapshot of the process, which they have obtained through electron microscopy. sweep. In an article published this week in «New England Journal of Medicine»Have made new analyzes that show what is the distribution and density of SARS-CoV-2 when it is infecting the lungs. Their results confirm the great potential of viral particles (virions) to infect the lungs.
The research, carried out by Camille honor, consisted of introducing the viruses into cultures of human epithelial cells that are found in the bronchi and that act as a barrier between the blood and the bloodstream. They allowed viruses and cells to come in contact for 96 hours and then fixed the samples to use scanning microscopy.
In this way, apart from obtaining impressive images, they were able to observe that each infected cell produces a very high number of virions. Specifically, they detected three million plaque-forming units (groups of virions with the capacity to infect), for each culture dish.
In the image of this article, the viruses (colored in pink in the image) are observed on the respiratory cilia (blue), along with some trace of mucus (green). Finally, it is those pink particles that are expelled when talking, screaming or coughing, when they are incorporated into drops of saliva and mucus.