Dr. Mehmet Oz on Thursday reacted to the Chinese government quarantining the epicenter of the coronavirus outbreak, explaining that such a virus is hard to contain once it begins to spread from person to person.

“It’s very hard to wall this in once it starts,” Oz told “Fox & Friends.”

Oz said that detecting symptoms of coronavirus such as fever, sore throat, runny nose, cough, and headache will not help quarantine methods.

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Oz went on to say, “It takes maybe a week for the symptoms to arise after you're infected, so if you’re on a plane and the person next to you has the virus and they get pulled in to quarantine, you’re still going to be walking through there.”

Oz said that the virus started from locals eating meat that had contact with infected rodents.

The Chinese government restricted travel in two additional cities after announcing a quarantine for the city of Wuhan -- the epicenter of the deadly coronavirus -- and suspended public transportation in the locations as of Thursday evening. The move comes as Beijing also announced the cancelation of major events indefinitely, including celebrations for the Lunar New Year.

Authorities in Huanggang, in Hubei Province, which is around 50 miles southeast of Wuhan, suspended bus and train service and temporarily closed enclosed venues like movie theatres and internet cafes, the city's public television said.

Rail service in Ezhou, a smaller city south of Huanggang, is also being stopped.

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In all, an estimated 18 million people will be impacted by the restrictions in an effort to stop the spread of the coronavirus, which so far has sickened over 500 people and has been linked to at least 17 deaths.

Fox News’ Brie Stimson contributed to this report.