Still, the commission acknowledged that the source of the virus and its path of transmission were not fully understood.

“The mutation of the virus still needs to be closely monitored,” the statement said.

Of the new patients found in Wuhan over the weekend, 66 were men and 70 women, and their ages ranged from 25 to 89, the health commission reported on Monday. It said that they mostly had symptoms such as fever, coughing and difficulty breathing.

Most people with the infection have contracted it through exposure to animals at a market in Wuhan that sells seafood and live animals, the authorities say. But the health commission in Wuhan said on Sunday that some people who had come down with the virus had no exposure to the market.

That acknowledgment raises the possibility that the virus could be present in other markets in Wuhan, experts said, adding to fears that more people might be at risk.

“If you cannot find the source and control the source of the virus, you cannot extinguish the fire,” said David Hui, the director of the Stanley Ho Center for Emerging Infectious Diseases at the Chinese University of Hong Kong.

Dr. Hui said the risk of the virus spreading from human to human on a broad scale appeared to be low, though he noted that the virus could mutate.

The World Health Organization said on Sunday that while its analysis indicated that limited transmission of the virus is possible, it remained unclear whether it can easily spread from one person to another. The group said it would continue to examine the issue.