A virologist who helped to identify the source of the SARS virus nearly two decades ago recently had some rather ominous things to say about the outbreak in Wuhan.

In an interview with Caixin, Guan Yi, a Hong Kong University professor specializing in infectious diseases, feared that the scale of the Wuhan virus may be 10 times greater than that of SARS, adding that the situation left him feeling “powerless.”

”I’ve experienced so much. I’ve never felt scared, most of them are controllable, but this time, I’m scared,” he told the news outlet on Thursday in regards to his recent trip to Wuhan to help discern the source of the virus.

Arriving in the city on January 21, Guan was critical of what he saw there including the alarming uncleanliness of local wet markets and the airport, even as the city was on high alert. After only a day in Wuhan, he decided that he needed to get out. He has since put himself into isolation.

When asked for his opinion, Guan was skeptical about how much good the Wuhan lockdown would do, noting that many residents had already left the city for the Spring Festival holiday and that the optimal time for quarantine had already passed.

He also explained that this new virus may prove more difficult to trace than SARS, which was chiefly transmitted by so-called “superspreaders.” So far, health authorities haven’t been able to trace the spread of the virus.