Since the outbreak of cluster ingenuity in Beijing, the cumulative number of confirmed cases in Beijing as of the time of writing has reached 106, and the current prevention and control work in Beijing has entered a state of war. Recently, when people talk about salmon color change, they are also thinking about a question – where exactly did the virus come from? In this regard, some of the new crown epidemic prevention and control experts have also made an interpretation.
Capital ‘basket of vegetables’ breaks epidemic prevention and control record
Let’s start with our focus on June 11.
On the same day, there was a confirmed case of new coronary pneumonia in Beijing. The following day, six confirmed cases were reported in Beijing.
As none of the above patients were imported overseas, Beijing’s record of no locally confirmed cases in the last 2 months was broken.
The situation of the outbreak suddenly changed, the relevant departments also began an emergency tracing, found that the above seven cases of patients are located in Fengtai District, Beijing, “new origin agricultural products wholesale market” has more or less linked – either to the market, or for the market’s self-employed, frozen seafood market sales men or drivers and so on.
The wholesale market of agricultural products in Xinfadi mainly deals in vegetables, fruits, seeds, grain and oil, meat, aquatic products, side foods, seasonings, eggs, tea and other agricultural and by-products. Since its establishment on May 16, 1988, Xinda “has become the largest wholesale market for professional agricultural products traded in Beijing, the capital and even in Asia, with a high visibility and influence in similar markets in the world”.
Nationwide, the New Origin Market has invested in the construction of 14 sub-markets, and in the Beijing area, more than 150 convenience stores and more than 300 people-to-people through-trains have been established in the Beijing area, making it a veritable “basket of vegetables” in the capital.
It is precisely because of the importance of the new origin market and the severity of the new crown outbreak, June 13 at 3 o’clock, the market was temporarily closed, market related personnel and environmental pollution into the investigation and assessment, close contacts have also been centralized isolation, the surrounding 11 communities began closed management.
A salmon pot?
After identifying the “transmission site” of the new origin market, people have focused on “imported salmon”.
On June 12th, a board used to cut imported salmon in the Xinfa market detected the new crown virus.
In addition to the confirmed cases on the same day, there are also staff in the fresh market frozen seafood market area, so people began to talk about imported salmon color change.
Based on this, including the United States, Carrefour, including the main business in Beijing overnight off all salmon merchandise, the daily store brand, salmon suppliers have been affected.
However, whether imported salmon really carries the new crown virus, it is not yet clear, the following reasons are:
On the one hand, there are several environmental samples in the market that are positive.
The CDC conducted a comprehensive test of the new site overnight on June 12, and conducted a non-discriminatory sampling of all wholesale farmers’ markets and large supermarkets in Beijing, resulting in a total of 5,424 environmental specimens and 1940 pharynx samples from market practitioners. A total of 40 environmental specimens were tested positive for environmental specimens in the new origin market.
In other words, the virus has been detected in several areas of the market, except that the salmon case board described above is the first positive environmental sample found.
As mentioned above, it is difficult to say whether the virus has been transmitted by other mammals or factors in the environment, which are of a variety of agricultural and by-products that are mainly engaged in the new market.
On the other hand, there is evidence that the receptors of the new coronavirus infected host are present in mammals, and that the new coronavirus is difficult to infect fish.
It is reported that this view has been reflected in the University College London research team published in the preprinted platform bioRxiv paper – the new coronavirus as a genus of beta coronavirus, the invasion host is generally through the S protein and the host cell ace2 receptor binding, so the virus is present in the deep-sea fish salmon salmon claims that there is a serious problem.
It can be seen that imported salmon is not free of viruses in the body is very likely.
Does the virus originate in the cold chain?
Of course, salmon is not the host, it is not so important – the door handle is not contained in the new crown virus, its surface can be contaminated with the new crown virus, causing the virus to spread, the same reason can also be used in salmon.
Recently, Tsinghua University Medical College, the Department of Basic Medicine, Professor Cheng Gong recently in an interview with China Newsweek, said that salmon as a virus attachment carrier or medium, so it is possible that fish in foreign countries contaminated, but in a cold chain way to import:
We usually keep virus samples, also in ultra-low temperature refrigerators, or -20 to -80 degrees.
Indeed, cold chain-related cases occur from time to time. For example, France Zero is a seafood counter staff, california fish treatment plant and South Korea’s Ministry of Marine Fisheries has also been confirmed cases.
As Guan Qi, director of the National Key Laboratory for New Infectious Diseases at the University of Hong Kong and director of the Influenza Research Center at the University of Hong Kong, said in an interview with China Newsweek:
The possibility of transmission through cold chains is greatest, with many abattoirs in Europe and the United States outbreak of new crowns. Cold chain transmission is not uncommon.
That said, at present, researchers are not able to determine the specific salmon in the slaughter, transport, packaging, cutting process of the specific link of the new crown virus, after all, the entire supply chain to trace the roots in the short term is not an easy task.
So, if imported salmon may be the carrier or medium of virus attachment, does it mean that the virus originated abroad?
When it comes to salmon imports, many people may think of a country, Norway.
According to salmon business, China imports about 100,000 tons of salmon each year. Among them, Chile, Norway, Australia, Canada and other countries of major imports. In the past 1-4 months, 45% of the frozen salmon imported into china came from Norway. At present, China has become the third largest market in the world for Norwegian seafood.
In fact, the researchers have given preliminary findings – this time the strain is more like Europe.
On June 15th Wu Zunyou, chief epidemiologist at the China Center for Disease Control and Prevention, said in a live broadcast:
Judging from the composition of the virus, the virus is not like the strain of beijing two months ago, more like Europe.
Wu Zunyou said that although the investigation of the source of the virus is still ongoing, but it is certain that this time is not in Beijing, is an external input.
It is worth noting that “strains from Europe” and “viruses from Europe” cannot be equated. The reason is that the “European strain” is a broader concept, either from European countries or from the Americas.
At present, although the exact source of the virus is not yet conclusive, but the prevention and control department in the first time to carry out a trace-setting, to determine the transmission path between confirmed cases, so we do not need to panic too much, I hope the outbreak will end as soon as possible.