By Huang Shan, Jing Hai: Despite the incident, the South China Seafood Market in Wuhan has been regarded as “the birthplace of all disasters”, gathering all eyes and discussions. But as scientists continue to study the spread of viruses and outbreaks, new possibilities are being proposed.
In the discussion of the origin of the new coronavirus, a report in Science magazine titled “Wuhan seafood market may not be source of novel virus spreading globally” pointed out that some scholars It is believed that the paper published in the latest The Lancet challenged this long-standing basic understanding that Wuhan South China Seafood Market is the birthplace of the virus.
(Source: The Lancet) Chinese scholars led the study. In the paper, they tracked the first batch of 41 confirmed cases and found that among the first batch of cases reported on December 1, a total of 13 cases had no history of contact with the seafood market.
The report said that the earliest case became ill on December 1 and there were no reports of links to the seafood market. “No epidemiological link was found between the first and subsequent patients.”
The 13 cases with no history of contact with the seafood market have drawn more attention from scientists. According to Science, Daniel Lucey, an infectious disease specialist at Georgetown University, said: “This is not a small number. 13 people have nothing to do with this market.”
Daniel Lucey said that if the data were true and accurate, the earliest infection would occur in November. Evolutionary biologist Kristian Anderson analyzed the genome sequences of 27 2019-nCoV viruses in order to find the source of the virus, and found that the source of the virus may appear as early as October 1.
In other words, the new coronavirus may originate from other places and then spread to the seafood market before triggering a subsequent large-scale concentrated outbreak.
The paper collaborator and Chinese scientist Cao Bin also told Science magazine that the South China seafood market may not be the sole source of the virus, but so far they do not know where the virus originated.
Figure 丨 “Science” magazine report (Source: “Science” magazine)
In the Lancet study, the researchers analyzed the first 41 confirmed cases of 2019-nCoV infection admitted to Wuhan between December 16, 2019 and January 2, 2020.
The average age of these 41 patients was 49 years old, and they were accompanied by common symptoms such as fever and cough. Of these patients, 32% were admitted to the intensive care unit (ICU) due to their severe condition, and 6 patients have died.
Researchers first divided diagnosed patients into ICU patients and non-ICU patients with severe illness who needed to enter the intensive care unit.
It can be clearly seen from the statistical information that the median age of the patients is 49 years, of which the proportion of patients aged 25-49 and 50-64 years is 49% and 34%, respectively. In terms of gender, male patients are the majority. Among 41 patients, 30 are male, accounting for more than 70%.
From this batch of patient data, we can see that the South China Seafood Market in Hankou , Wuhan is an important source of infection. Of the 41 patients covered in the study, 27 patients visited the market, which is close to one third. two.
Figure | Most of the early patients have a history of contact with the South China Seafood Market (Source: The Lancet)
As of January 22, 2020, 28 (68%) of the 41 patients included in the study were discharged.
The researchers also pointed out some of the limitations of the study, including the difficulty in accurately assessing risk factors related to disease severity and mortality due to the limited number of cases, and they called for larger studies in outpatient and community settings to confirm 2019-nCoV Complete disease spectrum of infected patients.
However, researchers and other experts who wrote the paper cautioned that these were small-scale studies with a limited number of patients in a rapidly evolving outbreak. But they point out that sharing this information as quickly and rigorously as possible can help shape the response.
Earlier reports from domestic authorities and the World Health Organization said that the first patient had symptoms on December 8th, and these reports simply said that “most” cases were related to the seafood market closed on January 1.
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According to Daniel Lucey, the first human infections occurred in November because there was a latent period between infection and the appearance of symptoms. If so, the virus could have spread silently between people in Wuhan and elsewhere, until a large number of cases emerged in the South China Seafood Wholesale Market in late December.
Lucey asserts: “The virus had sneaked into the lives of local people before entering the seafood market.”
Lucey also confirmed the possibility of this situation with the previous MERS epidemic.
As of June 22, 2017, the Middle East Respiratory Syndrome Coronavirus (MERS-CoV) has caused more than 2,000 infections and 700 deaths in 25 countries worldwide. The scientific community has long believed that the first patient of the Middle East Respiratory Syndrome (“Patient Zero”) was a 60-year-old man who appeared in Saudi Arabia in June 2012. However, one year after the virus outbreak, a follow-up study in 2013 found that as early as April 2012, eight Jordanian medical staff had respiratory symptoms, but it was not known at the time that this was the Middle East respiratory syndrome.
Later, researchers discovered the Middle East Respiratory Syndrome virus in blood samples from two of the dead cases, officially confirming that the earliest outbreak of the Middle East Respiratory Syndrome Coronavirus (which we know) was not Saudi Arabia, but Jordan.
Figure 丨 The scope of infection in the Middle East respiratory syndrome (Source: Wikipedia)
However, unlike the Middle East Respiratory Syndrome Coronavirus, which does not yet determine whether the natural host of the virus is a camel or a bat, numerous studies have shown that the natural host of nCov-2019 is likely to be a bat.
Moreover, the research progress of new coronaviruses from case discovery to virus isolation to epidemiology is significantly faster than that of the Middle East respiratory syndrome. Therefore, we have reason to believe that as more new coronaviruses nCov- Studying the blood samples of 2019 cases, we may find more clear evidence to find out how nCov-2019 spread from nature to human society.
Based on this, Lucey suggested that the blood samples of related human and animals (including suppliers from other animal markets) can be retrospectively analyzed as soon as possible, which may clear the fog of the origin of 2019-nCoV more clearly. There is a clear signal. ”
So far, Science has proposed another statement about the origin of the new coronavirus based on the study of the first 41 cases of the Lancet. Whether it is Lucey or Andersen, their inferences have only been published in interviews with media or on related websites, and they have not experienced the peer review necessary for publishing academic papers. Therefore, we are not sure of the correctness of their conclusions regarding the first case. Whether this statement holds is still waiting for more information.