Tracking the enemy: Will mutations make the virus less harmful?

Chennai

These mutations can also change the characteristics of a virus, causing the original virus to either weaken or become more aggressive. These different variants also explain why a virus can trigger infection waves of varying severity in different regions of the world, and why infections can also progress very differently in different people.

China, the country where the pandemic originated, had largely brought the spread of SARS-CoV-2 under control by imposing strict restrictions on movement. In recent weeks, infections had been found almost exclusively in people returning from abroad. Now, however, new infections have again been reported in some Chinese provinces, and this time the infections have obviously taken place in China. Initial tests have also shown that a new variant of the virus is now apparently circulating in China. The SARS-CoV-2 currently being found in Beijing differs slightly from the strain that previously afflicted China, Zeng Guang, an epidemiologist at the Chinese Health Bureau, told the Global Times newspaper. The results are now to be compared with analyses from other countries to trace the lineage of the virus.

The current trail of virus infection has led Chinese health authorities to cutting boards in Beijing’s Xinfadi wholesale market on which imported salmon had been processed. It is still unclear where the salmon came from, as China imports the fish from several countries, including Norway, Chile, Australia, Canada and the Faroe Islands. It is very surprising that salmon is now being thought responsible for the transmission of the coronavirus to humans because the risk of infection is highest from certain mammals. These include camels, horses, sheep, rabbits, martens, ferrets and cats. In contrast, fish, reptiles, amphibians and birds have been shown by many studies to be unlikely vectors of infection. What is decisive here is the structure of the ACE2 enzyme in the host animal, because the coronavirus has to dock into this enzyme in order to enter a body cell.

As a precautionary measure, the Xinfadi market was closed this past weekend. Around 10,000 dealers and employees at the market are now to be tested for SARS-CoV-2 as quickly as possible. In addition, several apartment blocks in the south of Beijing were sealed off, and nine schools and kindergartens were closed. The planned opening of primary schools in Beijing has been postponed, and sports events and group trips to other provinces have all been cancelled.

It has not yet been clarified beyond doubt where and how the novel coronavirus first appeared in humans. So far, researchers have assumed that the first mutations spread in Wuhan, China. The protein with which the virus docks to the cells probably mutated in a host animal, possibly a bat, a pangolin or a tanuki. This mutation allowed the virus to be transmitted to human cells.

There is much to suggest that the new wave of infections in China is being caused by a new mutation because this time the symptoms develop more slowly. However, there is no reason to panic, because a mutation does not necessarily make a virus more dangerous. In fact, some mutations can significantly weaken it.

Christian Drosten, a leading German virologist from the Charite hospital in Berlin, also sees any mutation of the novel coronavirus in quite a positive light. He believes it could enable the virus to “replicate even better in the nose and also be transmitted more effectively,” Drosten says, pointing to recent studies. A mutation that primarily affects the nasal area could enable the virus to multiply better, something which “leads to virus epidemics actually becoming more harmless over time,”

— This article has been provided by Deutsche Welle