2021-10-14

Can COVID-19 spread from animal to human two times?

By yqqlm yqqlm

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some researchers said that the earliest COVID-19 sequences were taken from infected patients at the end of 2019 and early 2020. They were divided into two genealogy, known as A genealogy and B genealogy. They had key genetic differences. A key question is how the two virus lineages are related. If lineage A virus evolves from lineage B virus, or on the contrary, it means that the original virus only spreads from animals to humans once. However, if the two virus lineages have different origins, there may be more zoonotic spillover infections</ The latest analysis published by p>

in the virology website discussion area challenged the existence of the genome of the associated A and B genealogy virus, which may be a “heart dagger” because this study can prove whether COVID-19 is manufactured by humans or from the assumption of wild animal trade. Other experts said that more research work is needed, especially the limited genomic data in the early stage of the pandemic

this is a very important study. If it can be proved that a and B are two independent virus sources and have two overflow transmission routes, the hypothesis of man-made virus will be completely eliminated

viruses of lineages A and B are defined by the differences of two key nucleotides, but some early genomes may combine these differences. Researchers previously thought that these genomes may be viruses in the middle stage of evolution, and the viruses of these two lineages need to be combined and analyzed, which is likely to have more primitive lineage viruses. The researchers conducted a detailed study based on the latest analytical background and noted some problems</ P>

researchers analyzed 1716 COVID-19 genomes, which were collected before February 28, 2020 and identified 38 such intermediate genomes. However, when they observed these sequences more carefully, they found that many sequences also contained mutations in other regions of the genome. They pointed out that these mutations must be related to a and B lineage viruses, which questioned the related virus genome dating back to the intermediate stage of evolution between a and B lineage viruses

when sequencing one of the two mutations in these “intermediate genomes”, laboratory or computer errors may occur. With comprehensive combing and analysis, researchers may not believe that there is any “transition genome”

researchers say that such sequencing errors are not uncommon. Software sometimes uses wrong gene sequences to fill the gaps in the original data, so that virus samples may be contaminated. This is not surprising, especially in the early stage of the pandemic

several researchers who sequenced virus samples wrote in the journal Nature that the virus gene sequence is unlikely to contain errors in two key nucleotides. But the study authors retort that even if some genomes are sequenced correctly, other parts of the same genome, or the location of sample collection, still clearly show that they belong to only one or another virus lineage

the virus spreads from animals to humans twice</ P>

if COVID-19 spread between animals and humans many times, previous studies have shown that the virus may have been transmitted from animal to animal many times. If the virus is man-made, then accidentally spread, and then spread the virus to the whole population, this must happen twice in order to have such a large-scale global disaster. Therefore, researchers tend to think that the epidemic originated from wild animals

in order to collect more evidence, the research team engaged in the latest analysis now plans to run computer simulation to test how many spillover infectious events match the genomic diversity of the known new crown. (Ye Qingcheng)