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A complete virus particle is called a "virion", which is composed of a protective "capsid" composed of proteins and a "nucleic acid" enclosed by the capsid. Outside the nucleocapsid, there is a membrane made of proteins, polysaccharides, and lipids called "envelope", which has "spikes", such as influenza viruses.
Secondly, why can alcohol kill viruses with "mantle"? Is it better to use high-concentration alcohol directly?
The reason why alcohol can be disinfected is because alcohol can absorb the moisture of virus protein, make it dehydrated, denatured and solidified, thereby achieving the purpose of killing the virus. If high-concentration alcohol is used, the virus protein will be dehydrated too quickly, and the surface protein of the virus will be denatured and solidified first, forming a strong envelope. Instead, the alcohol cannot penetrate the virus well, which will affect its ability to kill the virus. 75% alcohol is similar to the osmotic pressure of the virus. It can gradually and continuously penetrate into the virion before the virus surface protein is denatured, so that all the virus proteins are dehydrated, denatured and solidified, and finally killed the virus. When the alcohol concentration is lower than 75%, Due to reduced permeability, it will also affect the ability to kill viruses.
A well-known infectious disease expert, recently revealed that the new coronavirus can be extinct as long as it exists in an environment of 56°C for 30 minutes. In addition, using 75% medical alcohol, ether, and chlorine-containing disinfectants can effectively eliminate the virus. Alcohol can indeed kill most viruses, especially the coronavirus, while bleach can kill almost all viruses. Regarding his statement that “high temperature can kill the new coronavirus”, the high temperature must be at least 56°C and maintained for 20-30 minutes to effectively sterilize, but this is mostly used to clean equipment, and the general public does not use this It is a method of sterilization, but the people should be reminded that food must be cooked.
It is worth noting that the higher the alcohol concentration, the better the sterilization effect. Because the high concentration of alcohol will make the protein on the surface of the bacteria coagulate quickly, but this speed is too fast, and the alcohol cannot continue to penetrate into it. For some bacteria, its inside is still "alive", killing it is equivalent to Did not kill. The alcohol concentration with the best bactericidal effect is between 70-78%. Generally speaking, 75% alcohol can kill 99% of bacteria. Alcohol is a cheap, convenient and effective way to kill bacteria.
Alcohol can kill viruses because it can dissolve the "lipid envelope" of the virus. Therefore, a virus with a mantle like the "coronavirus" must be used for alcohol to function effectively. The method of using alcohol for disinfection and sterilization is to use 75% alcohol (the effect is even better than 95%) to wipe the surface of the skin or the surface of the object to achieve the disinfection effect. In addition, alcohol can also "deactivate, denaturation" the protein, so it will also inactivate the virus. The reason for dealing with viruses is not so simple, because viruses do not have a cellular structure, they are composed of DNA or RNA and proteins.
When they exist alone, they cannot grow and replicate independently, but they will not be eliminated. However, once the virus has found a host "Parasitic" can use the host's cell system to replicate and cause infection. Simply put, when there is no host, the virus is nothing.
It can barely be said to be a piece of "message"; but once it parasitizes a living organism, it will infect other living organisms vigorously. Viruses are not unkillable, but they are not as simple as bacteria and can be solved by alcohol. There are basically two ways to kill viruses. One is to heat to a specific temperature and continue for a period of time to denature DNA and RNA and lose their activity. The second is to use hypochlorous acid water, bleach and other ingredients that can destroy the outer shell of the virus protein.
75% alcohol is used for sterilization; 50% alcohol is used to prevent bedsores; 50% alcohol bath is used for physical cooling of patients with high fever. Different concentrations of alcohol have different effects. The reason why alcohol can be disinfected is because alcohol can absorb the water of bacterial protein, make it dehydrated, denatured and solidified, so as to achieve the purpose of killing bacteria. If high-concentration alcohol is used, the bacterial protein will be dehydrated too quickly, and the surface protein of the bacteria will be denatured and solidified first, forming a strong coating. Instead, the alcohol cannot penetrate into the bacteria well , thus affecting its sterilization ability. . 7 5% of alcohol and osmotic pressure similar to the bacteria, can penetrate into the interior continuously gradually before the bacterial cell surface proteins are not denatured, so that all the bacterial proteins dehydration, denaturation solidification, eventually killing the bacteria, when the alcohol concentration is less than 75% When the permeability is reduced, it will also affect the sterilization ability.
Therefore, if the concentration of alcohol is too high or too low for sterilization and disinfection, the best effect is 75%. Studies have shown that 70-78% alcohol can achieve 90% sterilization effect . 75% alcohol can destroy the lipid layer surface of germs, so it can sterilize and eliminate influenza viruses, but because enterovirus does not have adipose tissue, 75% alcohol It has no effect on spores and enterovirus.
Conclusion: With high concentration of alcohol, the dehydration effect makes the network structure more dense. In addition, the membrane protein rapidly loses water and solidifies to form a dense protective shell. The ethanol molecules cannot enter the cell interior and cannot achieve the purpose of sterilization.
Based on this sterilization mechanism, medical alcohol is a relatively broad-spectrum sterilization agent that can meet the needs of sterilization.
Comman Questions:
How do I disinfect surfaces during the coronavirus disease pandemic?
In non-health care settings, sodium hypochlorite (bleach / chlorine) may be used at a recommended concentration of 0.1% or 1,000ppm (1 part of 5% strength household bleach to 49 parts of water). Alcohol at 70-90% can also be used for surface disinfection. Surfaces must be cleaned with water and soap or a detergent first to remove dirt, followed by disinfection.
Cleaning should always start from the least soiled (cleanest) area to the most soiled (dirtiest) area in order to not spread the dirty to areas that are less soiled.
Cleaning should always start from the least soiled (cleanest) area to the most soiled (dirtiest) area in order to not spread the dirty to areas that are less soiled.
What is the best household disinfectant for surfaces during COVID-19?
Regular household cleaning and disinfection products will effectively eliminate the virus from household surfaces. For cleaning and disinfecting households with suspected or confirmed COVID19, surface virucidal disinfectants, such as 0.05% sodium hypochlorite (NaClO) and products based on ethanol (at least 70%), should be used.
Can the COVID-19 survive in drinking water?
Currently, there is no evidence about the survival of the COVID-19 virus in drinking-water or sewage.
Source of comman Questions: WHO