China CDC publishes study finding traces of COVID-19 virus at Wuhan market, not all agree

Genomic analysis of swabs taken from stalls, surfaces, cages, and machinery inside the market was expected to provide more insights about the spread of the virus at the location and was recently published in the journal Nature.

Why has the study split the scientific community?

According to the study, some of the samples collected at the site tested positive for the virus. The analysis also showed that animals, such as raccoon dogs, are susceptible to the virus and were also present at the location. Since the sample collection was done after the disease began to spread, the scientific community is split on how the data needs to be interpreted.

David Robertson, a virologist at the University of Glasgow, told the BBC that the study provided strong evidence for the animal-human spillover. Calling the analysis an important dataset that was now available for others to work upon, he added that it was compelling evidence that the animals were probably infected with the virus.

In the early weeks of the outbreak, there were two lineages of the virus, A and B, that were circulating, with only lineage B being found at the market. The China CDC paper has also confirmed that lineage A was also found in the samples it analyzed, further confirming that lineage A is not ancestral to B.

Others, however, are apprehensive of the findings and suggest that the findings are not conclusive that the virus spillover happened at the market. They hypothesize that the virus probably was brought to the market and not necessarily by an animal. Additionally, the study also fails to identify a specific animal host for the virus, which passed it over to humans, fueling the lab leak theory.

Alice Hughes, a conversation biologist at the University of Hong Kong, questioned the quality of the research after the study also found traces of panda, mole rats, and chimpanzee DNA in the market samples. Since killing a panda is punishable by death in China, Hughes is confident that there was no trace of a panda in the market, yet it showed up in the analysis.

This could be a result of contamination of the samples or improper processing of the data, both of which raise doubts over how much faith must be put in the findings.