U.S. health officials said they diagnosed a second patient with the China coronavirus after a Chicago woman returned from Wuhan with the infection, and they are currently monitoring 63 other potential cases here.

The cases currently being monitored in the U.S. stretch across 22 different states, including the first patient in Washington state and the new case in Illinois, Dr. Nancy Messonnier, the director of the National Center for Immunization and Respiratory Diseases, told reporters on a conference call hosted by the Centers for Disease Control and Prevention on Friday.

Officials said the patient, a woman in her 60s, is currently doing well and is in stable condition. She remains isolated in a hospital as a precaution, U.S. health officials said. The Illinois patient traveled to China in late December and began experiencing symptoms when she returned to the U.S. last week, officials said.

Upon returning to the U.S., the patient had very limited movement from outside her home and did not use public transportation or attend any large gatherings, they said.

“CDC believes the immediate risk to the U.S. public is low at this time, but the situation is evolving rapidly,” she said, adding that there is likely to be more cases in the coming days. “We have our best people working on this problem.”

The flu-like coronavirus, first identified on Dec. 31, has already killed at least 26 people and infected more than 900 worldwide.

On Tuesday, the CDC confirmed the country’s first case — a Washington state man who has been quarantined in a hospital outside of Seattle after flying back from Wuhan, China. The CDC said the man reached out to local health authorities last week once he started experiencing pneumonia-like symptoms.

U.S. health officials warned Friday that the flu or other respiratory illnesses could complicate identifying more cases.

“We’re really working to understand the full spectrum of the illness with this coronavirus,” Messonnier said. ”The problem with this time of year is it’s cold and flu season and there are lots of cold and respiratory infections circulating.”

This is a developing story. Please check back for updates.