BEIJING, March 9 (Xinhua) — The origin, transmission and evolution of the new coronavirus has attracted much attention since the outbreak of new coronary pneumonia. Several domestic and foreign experts said that, based on the existing evidence can not confirm where the new coronavirus originated. How did the spread of the new coronavirus in humans begin? From the initial reported cases, Wuhan’s South China seafood market was once considered the source of the outbreak.
Spreading “jigsaw puzzle” is missing
However, in a paper published in the British Lancet magazine in January, Huang Zhaolin, vice president of Wuhan Jinyintan Hospital, and others analyzed the first batch of 41 confirmed cases of new coronary pneumonia and found that only 27 of them had been to the South China seafood market. Retrospective studies suggest that the first confirmed patient became ill on December 1, 2019, had no history of exposure to the South China seafood market, nor had any epidemiological link with subsequent confirmed cases, and that his family had not experienced fever or respiratory symptoms.
Christian Anderson, a biologist at the Scripps Institute in the U.S., speculated that there could be three scenarios for the new coronavirus to enter the South China seafood market: it could be brought to the market by an infected person, an animal, or a group of animals, science reported.
This view is supported by a number of experts and research. Wilt Ian Lipkin, a professor at Columbia University’s Melman School of Public Health known as the Virus Hunter, said the link between the new coronavirus and the southern China seafood market may have been less direct, perhaps because of a “secondary spread” that had spread earlier.
Researchers at the Xishuangbanna Tropical Botanical Garden of the Chinese Academy of Sciences recently published a paper in preprinted form, saying they analyzed genomic data from 93 new coronavirus samples from 12 countries on four continents and found that they contained 58 monosizes, with individual samples associated with the South China seafood market being H1 or its derivative type, while H3 More “old” singles such as H13 and H38 come from outside the South China seafood market, confirming the view that the new crown virus in the South China seafood market is being introduced from other places.
To restore the new coronavirus transmission chain, scientists also lack some “jigsaw puzzles”, the most critical of which is the first infected person often referred to as “Patient Zero”. “Patient Zero” is the intersection of many questions that are critical to finding intermediate hosts and answering questions about how viruses can spread from animals to humans.
A famous example is the Spanish flu, which was estimated to have killed tens of millions of people worldwide a century ago, and although the outbreak was first reported in Spain, backtracking studies later found that the first infected person might have been a soldier from a military camp in Kansas.
Daniel Lucie, an infectious disease expert at Georgetown University in the United States, said the first new coronavirus infection could have occurred in November 2019 or earlier, taking into account factors such as the incubation period.
In terms of the global spread of the new coronavirus, while most cases of new coronary pneumonia can be traced to the source of infection, countries such as the United States have reported a number of untraceable cases. In Italy, where the epidemic is becoming more severe, its domestic “patient zero” has not yet been found.
Virus traceability not completed
The new coronavirus originated in animals, and how did it survive and evolve in nature before it entered the human body? In a paper published in the British journal Nature in February, researchers from the Wuhan Institute of Viruses of the Chinese Academy of Sciences said they found that the new coronavirus was 96 percent consistent with the gene sequence of a coronavirus in bats, or TG13. TG13 is the most similar strain to the new coronavirus gene known to date, suggesting that bats are likely to be the natural hosts of the new coronavirus.
Other studies have also found similarities between the new coronavirus and the coronavirus gene sequence carried by pangolins, especially in the receptor binding domain that allows the virus to enter the cell. This suggests that during the evolution of the new coronavirus, TG13 may have been recombined with the coronavirus carried by pangolins.
Although the research provides clues, several experts interviewed by Xinhua News Agency said the origin of the new coronavirus and intermediate host are still difficult to determine, the full origin of the virus may take longer.
Jonathan Bauer, a professor of molecular virology at the University of Nottingham in the UK, said the link between the new human coronavirus and pangolins remained a “small question mark” and no final answer had been given to the source of the virus. But if all the debris clues are put together, they point to an event where a virus is spreading from an animal.
Charlie Kalisher, a professor at Colorado State University’s School of Veterinary medicine and biomedical sciences, said he was open to discussing the source of the new coronavirus and that the conclusions needed to be supported by scientific data, not just guesswork.
Stanley Pearlman, a professor of microbiology and immunology at the University of Iowa in the United States, believes that animals that are intermediate hosts of the new coronavirus may come from outside China, such as smuggled pangolins.
The China-WHO Joint Study Report on New Coronary Virus Pneumonia (COVID-19), released at the end of February, also noted that “existing knowledge limitations” include “animal sources and natural hosts of the virus”, “animal-to-human infection processes in the initial stage” and “early exposure cases with an unknown history”.
The global epidemic is still spreading, and many questions remain to be answered by researchers from all over the world. As WHO Director-General Tan Desai has repeatedly stressed recently, in the global fight against the new coronary pneumonia epidemic, “facts, not fear” “need sage, not rumors” “need seduce, not stigmatization”. (Participating journalists: Zhang Ying, Zhou Zhou, Zhang Jiawei)