Particles like SARS-CoV-2 are very sensitive to temperature

Winter is coming in the Northern Hemisphere, and public health officials are asking how seasonal changes 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 a modest temperature rise failed Virus‘Structure, humidity had little effect. To maintain infectivity, SARS-Cov-2 membranes require a specific web of proteins arranged in a specific order. When its structure collapses, it becomes less infectious. The findings suggest that as the temperature begins to drop, the particles on the surface remain infectious for longer.

This is the first study to analyze the viral mechanism at the individual particle level, but the findings are consistent with large-scale observations of other coronaviruses that appear to infect more people during the winter. I will.

Michael Versinin, an assistant professor and collaborator at the University of Utah, said, “We expected the temperature to make a big difference, and that’s what we saw. Even moderate temperature increases completely destroy the virus package. Until. ” Senior author of the treatise. “The amazing thing is how little heat is needed to break them down. The surface is warm to the touch, but not hot. This virus package is very sensitive to temperature.”

The· paper Published online in the journal on November 28, 2020 Biochemical Biophysics Research Communication.. The team also published another treatise on December 14, 2020. Science report Describes how to create individual particle packages. Virus-like particles are empty shells made from the same lipids and three proteins as the active SARS-Cov-2 virus, but do not contain RNA that causes infection. This new method allows scientists to experiment with the virus without risking its outbreak.

SARS-CoV-2 usually spreads by sharp exhalation (such as sneezing or coughing) and emits small aerosol droplets from the lungs.These mucous droplets have a high surface-to-volume ratio and dry quickly, resulting in both moist and dry virus particles. surface Or go directly to the new host. Researchers have mimicked these conditions in experiments.

They tested virus-like particles on the glass surface in both dry and humid conditions. They used an atomic force microscope to observe how the structure changed. Scientists have exposed samples to different temperatures under two conditions. The particles in the liquid buffer and the particles dried outdoors. Raising the temperature to about 93 ° F for 30 minutes, both liquid and bare, deteriorated the external structure. The effect was stronger with dry particles than with liquid protected particles.In contrast, the surface at about 71 degrees Fahrenheit causes little or no damage and the particles in the room temperature Infectious conditions last for a long time, outside of conditions and cool weather.

They made little difference under the level of surface humidity, but scientists emphasize that humidity is probably important particle The aerosol is in the air by affecting the speed at which it dries. The research team continues to study the molecular details of virus-like particle degradation.

“When it comes to fighting the spread of this virus, we have to fight every particle individually, so we need to understand why each particle deteriorates,” Versinin said. “People are also working on vaccines and trying to understand how the virus is perceived. All these questions are single particle questions. If you understand that, it’s you swarming them. Allows you to fight. ”