At the end of 2019, the new crown epidemic broke out suddenly in Wuhan. China took swift action, proactively notified the epidemic information, adopted the most comprehensive and strict prevention and control measures, and achieved remarkable results in epidemic prevention and control.

At present, the epidemic is still spreading globally.

In order to guide and prevent the occurrence of future pandemics, China actively supports the World Health Organization in carrying out the global traceability of the new coronavirus.

According to the TOR agreed upon by China and the WHO in July 2020, the WHO dispatched an international expert group to Wuhan on January 14, 2021, and formed a joint expert group with Chinese experts, divided into epidemiology, The three teams of molecular traceability and animal and environment jointly carried out the work of global traceability in China.

The joint expert team has jointly studied a large number of epidemic-related data and materials, and inspected 9 units including Jinyintan Hospital, South China Seafood Market, and Wuhan Virus Institute of Chinese Academy of Sciences, and medical staff, laboratory staff, scientific research staff, market management staff and merchants. , Community workers, recovered patients, sacrificed medical staff’s family members, residents, etc. have conducted extensive exchanges, and continuously gathered scientific consensus. Joint research results have basically been formed, including:

　　Coronaviruses with a high degree of similarity to the new coronavirus gene sequence were found in bats and pangolins, but the similarity is not enough to make them the direct ancestors of the new coronavirus; animals such as mink and cats are highly susceptible to the new coronavirus, suggesting bats and pangolins Or weasel, cats, and other species may be potential natural hosts.

　　Environmental testing after the closure of the South China Seafood Market generally found COVID-19 contamination, especially in aquatic product stalls. The COVID-19 may be introduced through infected persons, contaminated cold chain products, animal products, etc., but it is still uncertain.

Large-scale testing of animal products in this market did not find positive. No new coronavirus was found in bats in Hubei Province and a large number of livestock, poultry, and wild animals throughout China. No new coronavirus was found in livestock, poultry, and wild animals before and after the outbreak. Circular evidence.

　　In December 2019, a certain scale of transmission of the new crown virus occurred among the population of Wuhan, and most of the cases were concentrated in the second half of the month.

The South China Seafood Market is one of the outbreak points of the new crown epidemic, and it is also a key place that attracted the attention of the disease control department in the early stage of the epidemic. However, early case searches and analysis showed that while cases appeared in the South China Seafood Market, cases also occurred in other places in Wuhan.

　　The joint expert group conducted a scientific evaluation of the possibility of the new coronavirus being directly transmitted from the natural host and introduced into the population through four ways of cold chain food, intermediate hosts, and laboratories (the assessment conclusions are divided into "extremely impossible" and "impossible" , “Probable”, “more likely”, and “very likely”), it is believed that the new coronavirus is “more likely” to be introduced into the population through an intermediate host, or “probably” is directly transmitted or introduced into the population through cold chain food, “very "Impossible" is to introduce people through the laboratory.

　　The joint expert group also made recommendations for the next step of global traceability.

(Xu Zhihao Zhang Wen, CCTV reporter)