Yes, there is DNA from raccoon dogs in the swab samples that Chinese researchers collected in January and February 2020 from cages and surfaces of the now-cleared Huanan market in Wuhan. This may indicate that these animals were the source from which the coronavirus first infected humans, but alternative explanations have still not been ruled out.
This connection between the raccoon dog and the notorious Huanan market, which is considered the source of the corona pandemic, came to light when a group of Western scientists discovered on March 9 that their Chinese colleagues had previously unknown genetic sequences in an international virological database (GISAID). ) had set. It turned out to be the raw analysis of environmental samples collected by the Chinese infectious disease agency CDC shortly after the closure of Wuhan’s Huanan market, to which many of the early corona infections could be linked.
These environmental samples had already been mentioned in a preprint that the Chinese researchers put it online as early as February 2022. At the time, the Chinese showed that genetic material from SARS-CoV-2 could be found in those samples, but not whether they also contained human or animal DNA. With the raw genetic data that Western scientists have now discovered, that analysis could still be done. They discovered human DNA and DNA from numerous corona-sensitive animals in the samples; an important fact in the search for the origin of the coronavirus.
Three years later
The fact that this has only come to light now, three years later, is an international embarrassment for China. This again shows that the country has not provided all relevant information about the origin of the pandemic. Not even when an international delegation from the World Health Organization visited Wuhan in February 2022 to investigate the origin of the virus. Moreover, the genetic data were already removed from the GISAID database on March 11, after the Western researchers had informed their Chinese colleagues of their findings. It led to frustrated reactions from the WHO on Friday, where scientists discussed the results of the study in private last week. “Any data that could shed light on the origins of the pandemic must be shared immediately,” said Maria van Kerkhovetechnical director at WHO, at a press conference Friday.
After the American magazine The Atlantic reported about it as “the strongest evidence to date” that the pandemic started from an animal and not a lab sparked a debate about how strong the new evidence was. But without publication, no one could check whether it made sense. Until the group of Western scientists finally now, in the night from Monday to Tuesday, published their results in a preliminary preprint. In an effort to “promote transparency,” they write in an explanation.
It turns out that the researchers went in a very targeted search for the DNA of corona-sensitive animals. The samples often contain a mixture of DNA traces from different animals, including human DNA. But six samples taken from two vendor stalls in the southwest corner of the market were found to contain raccoon dog DNA. One of those samples taken on a cart contained a lot of raccoon dog DNA and no detectable human DNA. Because exactly that southwest corner corresponds to a previously defined hotspot of early virus infections among the merchants and visitors, the researchers strongly suspect that the source of the virus must have been there. Research has shown that the raccoon dog is sensitive to corona and, once infected, the infection can spread quickly. That is why the researchers now point to this animal as a possible initiator of the infection, which soon spread from person to person.
DNA traces
But the question is whether this suspicion can lead to definitive conclusions. DNA traces can show that a certain animal has been there, but the presence of virus material in that same sample does not prove that this animal has actually been infected. The researchers themselves emphasize this in their manuscript: the most common animal in the genetic samples is not necessarily the source of the virus in the sample.