Changes in new cases in Japan. Photo: NHK
According to a recent report by Japan's Kyodo News Agency, after reaching its peak in August this year, the number of cases in Japan began to decline sharply, and the number of daily cases fell from 25,000 to about 200 at present. In October, the number of new confirmed cases in Japan fell sharply. On October 15, the number of new cases in Japan was only 151, a new low, and on October 31, there were only 229 new cases in Japan, even in the "hardest hit area" Tokyo, there were only 22 new cases.
Compared with august 20 this year, when the number of new cases in Japan exceeded 25,800, the recent slowdown in Japan is obvious.
The duplicity of viral mutation results
Theoretically, there are two main factors for the improvement of the epidemic situation in Japan, one is that the epidemic prevention policy is appropriate, and the other is that the clinical prevention and control is strong. However, Japanese researchers believe that it is mainly the virus mutation that has had favorable but unfavorable results for the virus. Moreover, this is based on research and is not speculative and analytical.
Research recently published by the research team of the National Institute of Genetics and Niigata University in Japan showed that in the genome of the Most Toxic and Faster Transmission Of the Delta Variant strain that plagues countries around the world, an enzyme called nsp14 has mutated, causing the virus to fail to complete repair in time, making the virus self-extinction. Obviously, this is one of the results of the mutation of the virus.
In May this year, during the severe epidemic in Japan, there were many cases of underreporting and underreporting. Photo/CCTV screenshot
From the perspective of biological evolution theory, there has long been a dispute between the terms "evolution" and "evolution". The reason some people prefer to call evolution rather than evolution is that evolution has semantically preconceived notions that the evolution of living things develops only in the direction of biological benefits.
However, in fact, the changes in all living things, including humans, can only be summarized by evolution, because evolution is random, and can develop in the direction of the good of the organism itself, and can also develop in the direction of the unfavorable life itself, such as the extinction of the dinosaurs and the demise of neanderthals.
The same is true of mutations in viruses, which result in at least two types of mutations, one positive choice and one negative choice. The former is good for the virus itself, and the latter is bad for the virus itself.
Favorable results for the virus have also been seen, with its increased toxicity and accelerated transmission, such as the Delta variant, which has led to multiple outbreaks.
However, this is only one side of the coin. Even the most toxic and fastest-spreading Delta variants have many more subspecies, with studies to date showing that deltas have more than 40 subspecies.
Subspecies AY.4.2, a faster-spreading Delta variant, has also emerged in the UK and some parts of the world, with a spread rate of about 10% more than Delta (B.1.617.2).
And even the subspecies variation of the Delta variant is not just moving in favor of the virus, but has another outcome, namely negative selection.
This choice is bad for the virus and good for its host, humans. The current results of the Japanese study show this, which not only proves the duality or pluralism of biological evolution, but also presents a new situation that needs attention to the fight against the epidemic and is beneficial to mankind.
The evolutionary path that needs to be further confirmed
From the scientific point of view, the negative choice of virus mutation found this time is a problem with viral genome repair. Recent research by British researchers believes that the new crown virus is one of the fastest mutated viruses, mutating almost once a week, and the rate of mutation is more than 50% higher than previously estimated.
Infographic. Figure/IC photo
Genes and genomic variants in all organisms, including humans, initiate a fundamental function of living things, the repair of genetic material (DNA and RNA) to correct the mutated genes. The new coronavirus needs to help repair its mutated RNA gene by nsp14 enzyme, but if the enzyme nsp14 that repairs the mutated gene also mutates, it will lead to untimely or impossible repair.
In this way, too many mutant genes can lead to the inability of the virus to multiply, so the virus's ability to invade human cells decreases, or it itself dies and can no longer harm the human body.
Of course, the Japanese study may be isolated evidence, and other studies are needed to circumstantially prove it or prove it multiple times to confirm that the mutation of the new crown virus also has negative options.
At the scientific level, however, there is already circumstantial evidence. Japanese researchers speculate that enzyme-to-enzyme interactions led to mutations in the NSP14 enzyme, one of which is called APOBEC that alters the NSP14 enzyme. In East Asia and Oceania, this enzyme is particularly active in many people.
At the same time, combined with the changes in the epidemic situation in Japan, it is also consistent with the variation of NSP14 enzyme. In the fifth wave of the outbreak in Japan, infection caused by the nsp14 enzyme variant virus accounted for almost all infections during the period from the peak of the number of cases to the time of subsidence.
The third wave of the epidemic in Japan from last fall to around March this year also has this characteristic, indicating that the mutation of the new crown virus does have a negative choice and is headed for extinction or another evolutionary path of reduced toxicity and infectivity.
Of course, the Japanese study still needs the results of epidemic studies in other countries to confirm, but at least Japan's research and epidemic trends are in line with evolutionary theory, and there is also preliminary scientific evidence to support, which deserves further attention.
Beijing News special writer | Zhang Tiankan
Edit | Chi Daohua
Proofreading | Li Lijun