Thanks to Dr. Camille Ehre from the University of North Carolina and an electron microscope, we can see how the SARS-CoV-2 virus multiplies in our respiratory tract. The American biochemist published the photos in the New England Journal of Medicine.
To understand the size scale, keep in mind that each SARS-CoV-2 virus particle (virion) consists of a spiked-spherical protein shell surrounding genetic material approximately 50-200 nanometers (a nanometer is one millionth millimeter).
The photos were additionally colored by Cameron Morrison, a medical student at the same university. The hair-like structures are the cilia which have been given a blue color, the mucus streaks are yellowish-green, while the main character of the SARS-CoV-2 photos is red.
Dr. Ehre’s team infected a laboratory culture of bronchial epithelial cells that form a barrier between the air in the lungs and our blood with the coronavirus. The photos show the condition of the farm after 96 hours. They were made using a scanning electron microscope.
Researchers noted that “virus production in culture was approximately 3 times 10 to the power of 6 plaque forming units (PFU), which is consistent with the large number of virions produced and released per cell.”
PFU – plaque forming units, determine the number of pathogens in the test material when inoculated.
One of the photos is a broader view of the cilia, with small red virus particles visible, the other is a close-up, clearly showing the structure and density of the viruses.
Cilia occur in the intestines and lungs. They protect our respiratory system against pathogens and keep the lungs moist. The ciliated epithelium cleans the respiratory tract thanks to the movement of cilia that move viruses, bacteria and pollutants inhaled with the air outside the body.
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“These photos are an argument for wearing masks”
The photos show how large a number of virions are produced when a virus attacks our cells. The virions are expelled from the body in an aerosol generated when we cough, talk, and even breathe. Then they hover for some time.
According to scientists, we should consider the photos in a broader context.
– The scale of multiplication of the virus is the source of the infection spreading to other organs of the infected person. It probably also contributes to the high level of COVID-19 transmission. These photos are a strong argument for wearing masks by both infected and uninfected people, says Dr. Ehre.
See also:
- 30 million infected with SARS-CoV-2 in the world. Over 945 thousand deaths
- When will we come back to life before the pandemic? WHO: Maybe as late as 2022
- How does COVID-19 damage the brain?