More than 100 people, including those who have recently returned from mainland China, have been quarantined and are being monitored by the Dallas County health department, the agency’s chief said Monday.

None has tested positive, Dr. Phil Huang said Monday evening in an interview with The Dallas Morning News. Those under watch are reporting their temperatures and any other symptoms to the health agency twice a day, he said.

Huang declined to provide a more specific number – including whether any have been cleared – and said the department has no plans to provide more granular data. However, he reiterated, the department will notify the public if a positive test comes back.

The previously unreported number comes days after neighboring Collin County said that its health department is monitoring nearly 50 possible cases of the new virus known as COVID-19.

“It’s not time to panic, but everyone needs to be prepared,” Huang said. “We’re trying to get people thinking about all the things they may have to do.”

Huang is expected to brief the Dallas County commissioners Tuesday at their regularly scheduled meeting.

Elsewhere in Texas, 91 Americans were brought to San Antonio’s Joint Base San Antonio-Lackland after traveling to Wuhan, China, for testing. On Saturday, one woman was “mistakenly released” from isolation and later tested positive for coronavirus. San Antonio Mayor Ron Nirenberg on Monday declared a public health emergency in the city.

As part of its work to prepare for a severe outbreak in North Texas, the Dallas health department has participated in daily conference calls with state and federal agencies. It also has regularly updated guidance to more than 28,000 physicians, elected officials and health advocates. Additionally, it has begun building a lab to test for the virus locally, Huang said.

The lab should be up “shortly,” he said, but didn’t give specifics on when it would be ready or its location. It’s unclear how many tests for the coronavirus the county will need, he said.

Huang said his department has been working late nights and through the weekend to keep the most up-to-date information flowing. The Centers for Disease Control and Prevention has begun to issue more specific information for different populations, which the Dallas health department is passing out here.

And there are more recommendations coming, including what to do about large-scale public events, Huang said.

“It’s a big stress on our system,” he said, noting the additional burden of managing the regular flu season.

Huang urged businesses, schools, faith-based institutions and other groups to update their own pandemic plans to ensure that they’re ready if the virus becomes widespread.

“Dallas is not at the epicenter,” he said. “But we’re certainly addressing this very seriously.”