Dr. Nancy Messonnier, director of the Centers for Disease Control and Prevention’s (CDC) National Center for Immunization and Respiratory Diseases, warned that the spread of China’s deadly coronavirus in the United States is all but certain and said Americans’ everyday life could be dramatically affected.

“As more and more countries experience community spread, successful containment at our borders becomes harder and harder,” Messonnier told reporters on Tuesday afternoon.

“It’s not a question of if this will happen but when this will happen and how many people in this country will have severe illnesses,” the top public health official added. “Disruption to everyday life might be severe.”

Messonnier said the continued spread of the virus has led to a shift to a more dire tone.

“The data over the last week and spread in other countries has certainly raised our level of concern, and raised our level of expectation that we are going to have community spread here, so that has changed our tone,” she said.

The illness that originated in the Chinese city of Wuhan has now infected more than 80,000 people globally. 77,000 cases have been confirmed in China with others in parts of Europe and the Middle East.

To date, 57 cases have been confirmed in the U.S., including 40 cases of people who the government transported from the Diamond Princess cruise ship from Japan.

The virus’ spread caused the U.S. stock market to plunge.

An expected rebound after Monday’s 1,000-point nosedive on Wall Street had yet to materialize by midday Tuesday.

The Dow Jones Industrial Average was down nearly 500 points by 1 p.m. EST. The S&P 500 was down about 50 points and the Nasdaq 122 points.

The 10-year Treasury yield hit a record low of 1.32 percent Tuesday while the 30-year bond also fell.

Some experts anticipated at least somewhat of a rebound Tuesday, which has usually been seen following precipitous drops on a Monday, particularly after futures indicated a boost.

The Associated Press contributed to this report.