ksc thanks for making clear definitions of "strain" "variants". [url]https://en.wikipedia.org/wiki/Strain_(biology)#Microbiology_and_virology[/url] or https://en.wikipedia.org/wiki/Strain_(biology)#Microbiology_and_virology ; It has been said that "there is no universally accepted definition for the terms 'strain', ' https://en.wikipedia.org/wiki/Variant_(biology)" style="text-decoration: none; color: rgb(11, 0, 128); background: none;" title="Variant (biology) - variant ', and 'isolate' in the virology community, and most virologists simply copy the usage of terms from others". https://en.wikipedia.org/wiki/Strain_(biology)#cite_note-KuhnBao2012-2" style="text-decoration: none; color: rgb(11, 0, 128); background: none; - [2] A strain is a https://en.wikipedia.org/wiki/Genetics" style="text-decoration: none; color: rgb(11, 0, 128); background: none;" title="Genetics - genetic variant or subtype of a microorganism (e.g., a https://en.wikipedia.org/wiki/Virus" style="text-decoration: none; color: rgb(11, 0, 128); background: none;" title="Virus - virus , https://en.wikipedia.org/wiki/Bacterium" style="text-decoration: none; color: rgb(11, 0, 128); background: none;" title="Bacterium - bacterium or https://en.wikipedia.org/wiki/Fungus" style="text-decoration: none; color: rgb(11, 0, 128); background: none;" title="Fungus - fungus ). For example, a "flu strain" is a certain biological form of the https://en.wikipedia.org/wiki/Influenza" style="text-decoration: none; color: rgb(11, 0, 128); background: none;" title="Influenza - influenza or "flu" virus. These flu strains are characterized by their differing isoforms of surface proteins. New viral strains can be created due to mutation or swapping of genetic components when two or more viruses infect the same cell in nature. https://en.wikipedia.org/wiki/Strain_(biology)#cite_note-3" style="text-decoration: none; color: rgb(11, 0, 128); background: none; - [3] These phenomena are known respectively as https://en.wikipedia.org/wiki/Antigenic_drift" style="text-decoration: none; color: rgb(11, 0, 128); background: none;" title="Antigenic drift - antigenic drift and https://en.wikipedia.org/wiki/Antigenic_shift" style="text-decoration: none; color: rgb(11, 0, 128); background: none;" title="Antigenic shift - antigenic shift . Microbial strains can also be differentiated by their genetic makeup using metagenomic methods to maximize resolution within species. https://en.wikipedia.org/wiki/Strain_(biology)#cite_note-4" style="text-decoration: none; color: rgb(11, 0, 128); background: none; - [4] This has become a valuable tool to analyze the https://en.wikipedia.org/wiki/Microbiome" style="text-decoration: none; color: rgb(11, 0, 128); background: none;" title="Microbiome - microbiome . DJ-The general picture on the early stages of the pandemic already was not very good. With France, Spain, Italy finding cases (in retro spective) before China did see its first cases becoming known in the west.
------------- We cannot solve our problems with the same thinking we used when we created them. ~Albert Einstein
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