Winter is coming in the northern hemisphere and public health officials are wondering how the seasonal trend will affect the spread of SARS-CoV-2, the virus that causes COVID-19?
A new study tested how temperature and humidity affect the structure of individual SARS-Cov-2 virus-like particles on the surface. They found that only a moderate temperature rise broke down the structure of the virus, although humidity had little effect. To remain infectious, the SARS-Cov-2 membrane requires a specific network of proteins arranged in a specific order. When that structure falls apart, it becomes more contagious. The results show that as the temperature begins to drop, surface particles will remain infectious for longer.
This is the first study to examine the mechanics of the virus at an individual grain level, but the findings agree with major observations on other coronaviruses that appear to infect more people over months. winter.
You’d expect the temperature to make a big difference, and that’s what we’ve seen. To the point where the packaging of the virus was completely destroyed by even a moderate increase in temperature. What is surprising is how little heat is needed to break them down – a surface that is warm to the touch, but not hot. The packaging of this virus is very sensitive to temperature. “
Michael Vershinin, Associate Professor, University of Utah
The paper was published online on November 28, 2020, in the journal Biophysical Biochemical Research Communication. The team also published a separate paper December 14, 2020 in Scientific Reports describes their method of packing the individual grains. The virus-like particles are empty shells made from the same lipids and three types of proteins as those of active SARS-Cov-2 viruses, but without the RNA that causes infections. This new method allows scientists to try the virus without destroying a revolution.
The SARS-CoV-2 is commonly transmitted by sudden ejaculation, (e.g. sneezing or coughing), which emits droplets of tiny aerosols from the lungs. These mucus-y droplets have a high surface-to-size ratio and dry quickly, so both wet and dry viruses come in contact with the surface or travel directly into a host. new. The researchers simulated these conditions in their experiments.
They tested the virus-like particles on a glass surface under dry and humid conditions. Using an atomic force microscope they saw how the structures changed, if at all. The scientists exposed samples to different temperatures under two conditions: with the particles inside a melting buffer solution, and with the grains dried outside. In melt and bare conditions, the temperature rose to about 93 degrees F for 30 min of the outer structure. The effect was stronger on the dry grains than on those under liquid protection. In contrast, a surface at around 71 degrees F did very little damage, suggesting that particles in room temperature or outdoors in colder weather would stay infectious longer.
They have seen little difference under surface moisture levels, but the scientists confirm that humidity differs when the grains are in the air by affecting the speed at which the aerosolas drying. The research team continues to study molecular details of virus-like granule reduction.
“When it comes to fighting the spread of this virus, you have to fight with each grain individually. And so you have to understand what causes each individual grain. to go down, “Vershinin said. “People are also working on vaccines and trying to understand how the virus is identified? All of these questions are one-sided questions. And if you understand that, that gives you a chance to fight against a source of them. “
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Magazine Reference:
Sharma, A., et al. (2020) Structural stability of SARS-CoV-2 virus as particles declines with temperature. Biochemical and Biophysical Research Communication. doi.org/10.1016/j.bbrc.2020.11.080.