It is becoming more and more like that the outbreak of the new coronavirus has not started on the fish market in Wuhan. Finding the source can help prevent another pandemic.
As the world struggles to control the corona pandemic, a mystery remains: how and when was the virus transmitted to humans? Doubts are growing about the idea that this happened at the Huanan fish market in Wuhan, China, in December. Researchers are now trying to find out what the real source is. In doing so, they hope to prevent other, new coronaviruses from causing pandemics in the future.
Not in December anyway
According to a study of the first 41 hospitalizations of people with the coronavirus, a man who showed symptoms on December 1, 2019 was the first corona patient. Unlike the majority of the first group of patients, he had no connection whatsoever with the Huanan fish market.
Since then, no one has been able to confirm where he contracted the virus. It is also unclear whether he was really the first person to catch the virus. Another analysis of the first 425 corona patients, conducted in January by the Chinese Center for Disease Control and Prevention and the Chinese National Health Commission, places the first confirmed infection a week later: on December 8.
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But new evidence suggests that the outbreak started before December. Analysis of the viral genome – the entire genetic material of the virus – suggests that the virus was transmitted from animals to humans as early as November. But it could have happened as early as September.
Pneumonia
These results are in line with a message in the South China Morning Post which cites documents from the Chinese government. These indicate that the first corona infection occurred in a 55-year-old person from Hubei Province, who appears to have contracted the virus on November 17.
The first reported cases, dated December, were reported by Wuhan physicians who followed a surveillance protocol designed to identify pneumonia of unknown cause. This system was set up after the SARS outbreak in 2002-2003 to detect new viruses.
As far as we are at New Scientist The initial efforts of the Chinese authorities subsequently focused on people with viral pneumonia who had traceable links or contacts with the Huanan market.
This focus on pneumonia may have caused many mild early infections to be missed. By December, the infection had probably spread beyond Wuhan. A study of six children who contracted the coronavirus led to the identification of a girl who developed symptoms on January 2. She and her family live in Yangxin, more than 150 kilometers from Wuhan. None of them had been outside the province for the month before she became ill. Investigators couldn’t figure out how she got infected.
Many animals with coronaviruses
An explanation for this may be that the virus has spread from animals to humans several times. Bats are suspected of being a “reservoir” for the coronavirus, but vet Richard Kock of Royal Veterinary College London says it is highly unlikely that you can catch the virus from an accidental encounter with a bat. A more plausible explanation is that other animals served as intermediaries. These animals amplified the virus and made it possible to infect multiple people through a trial and error method, he says.
The coronavirus appears to be able to infect a wide variety of carriers. Lab studies show that rhesus monkeys and ferrets are easily infected. Javan pangolins could also be an intermediate carrier, because they already carry other coronaviruses that are comparable to the new coronavirus that we are currently facing. Genetic analysis led to the discovery of coronaviruses in pangolins that are more than 90 percent similar to the new coronavirus, but none of them seem enough to be the direct precursor.
It is currently unclear whether the Huanan market has played a role in transmitting the virus from animals to humans. “The problem is that most of the samples taken in the fish market have since been destroyed,” said infectious scientist Shan-Lu Liu of Ohio State University in the United States.
Patient zero
“It is still possible that the contamination in the fish market was the result of infected people working there instead of an animal source,” said medical statistician Benjamin Cowling of the University of Hong Kong.
The market is also only one of 400 in Wuhan. “If there has been a population of infected animals that have been delivered to 400 markets, and directly to restaurants, there have been many opportunities for the virus to jump,” said Kock.
Now that the virus has spread all over the world by jumping from person to person, some think it is hunting patient zero – the first person to become infected – is relatively insignificant. “At this point in the epidemic, it is not most important to know where it came from,” said epidemiologist Julien Riou of the University of Bern in Switzerland.
Prevent pandemics
But Kock finds identifying the source of the outbreak crucial. Especially given the fact that three coronaviruses – SARS, MERS and the new coronavirus – have emerged since 2002. “In evolutionary terms, that is in microseconds,” he says. “The risk of this kind of thing happening has increased enormously. We need to get a grip on that. “
More knowledge about how the new coronavirus has spread to humans can help prevent these kinds of events in the future, Cowling says.
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