The scientists, including a doctor trained by the Chinese military, cloned a pangolin coronavirus and infected modified mice to “assess its pathogenicity.”

Of the four mice infected with the virus, all began to lose weight five days post-infection. Shortly thereafter, they exhibited symptoms including sluggishness and white eyes.

The four mice died within eight days of inoculation. Researchers described the results as “surprising.”

Researchers then infected eight additional mice, euthanized them, and selected organs from four to analyze. High levels of viral RNA were found in various organs, including the brain, lungs, and eyes. While the viral load in the lungs decreased by the sixth day, it increased in the brain.

“This finding suggested that severe brain infection during the later stages of infection may be the key cause of death in these mice,” the scientists said.

The experiments were on a mutant strain of the pangolin virus, known as GX_P2V(short_3UTR).

The results suggest a risk for the virus to “spill over into humans,” researchers said.

Experts Concerned

Justin Kinney, an associate professor at the Simons Center for Quantitative Biology at Cold Spring Harbor Laboratory in the U.S., said the research described in the paper does not seem to fall under the category of gain-of-function because the Chinese scientists did not purposefully enhance the virus to be more pathogenic or transmissible.

“The research is still very dangerous, though,” Mr. Kinney told The Epoch Times via email. “I am especially concerned that the paper does not say what biosafety level the work was performed at. Coronavirus research in China is often done at a biosafety level (BSL-2) that is inadequate for working with potential pandemic pathogens that might be transmitted by air.

“Indeed, coronavirus research done at BSL-2 may have caused the COVID-19 pandemic. And by showing that the coronavirus has a surprisingly high pathogenicity, the work underscores the need for extreme caution when working with novel coronaviruses.”

The first COVID-19 cases were detected in Wuhan, China, near a laboratory that has conducted risky experiments on coronaviruses, including enhancing the pathogenicity of a bat coronavirus. Some scientists believe that the virus causing COVID-19 likely originated from the lab, given its history and the fact that, years later, a natural origin has yet to be identified.

Lihua Song, a scientist in Beijing who co-authored the new paper, did not respond to a request for comment on how the scientists ensured the experiments they performed were safe.

Critics noted that the researchers who published the new study include Yigang Tong, who was trained in a Chinese military program and worked in military-run labs. He also co-authored a paper in 2023 with Zheng-Li Shi, who helps run the Wuhan Institute of Virology.

Justin Goodman, senior vice president of the White Coat Waste Project, a U.S. nonprofit, said the new study added to the body of evidence showing Chinese scientists have been conducting “dangerous and deadly tests on mice.”

“This is why shipping US tax dollars to foreign adversaries’ unaccountable animal labs is a recipe for disaster and we’re working with lawmakers to stop it,” Mr. Goodman told The Epoch Times via email.

The U.S. National Institutes of Health (NIH) has for years funded lab work in China and other foreign countries, including testing done in Wuhan.

This week, Congress is focusing its questioning of Dr. Anthony Fauci on some of those experiments. Dr. Fauci has, for years, led the NIH office responsible for funding this work.

Results Unclear

The Chinese scientists infected genetically engineered mice that have lungs modified to better mimic humans. The outcomes were not compared with other live viruses, such as SARS-COV-2, which causes COVID-19.

That makes it unclear whether the pangolin coronavirus “is generally more dangerous than SARS-CoV-2, or if their results are due to the specific mice they used,” said Mr. Kinney. “And it’s not at all clear from their results what might happen were a human to become infected with this coronavirus.”

Mr. Kinney helped co-found a group called Biosafety Now that advocates for independent oversight of risky experiments.

Dr. Tong and his colleagues compared the pathological changes in the mice with those in a control group and found no evidence of severe inflammation. They noted that these results were consistent with reports from Shi regarding the pangolin coronavirus, as well as with their previous experiments conducted on golden hamsters and another type of mouse.

The researchers called for more investigation of the high pathogenicity of the coronavirus and said that their study “offers a distinct alternative model for understanding the pathogenic mechanisms of SARS-CoV-2-related coronaviruses.”