Stocks dropped for the fourth day in a row on Tuesday as the government warned Americans that the coronavirus was likely to upend daily life.

“It’s not so much of a question of if this will happen in this country anymore but a question of when this will happen,” Dr. Nancy Messonnier, a top official at the Centers for Disease Control and Prevention, said in a conference call with reporters on Tuesday.

The Dow Jones Industrial Average fell by as more than 879 points, around 3.15 percent, adding to the steep 1,000 point decline Monday. The S&P 500 dropped 3 percent and the Nasdaq Composite fell 2.7 percent.

The declines put both the Dow and S&P 500 more than 7 percent below record highs reached in February. The Nasdaq is more than 8 percent below the all-time high hit in February.

“We are asking the American public to work with us to prepare in the expectation that this could be bad,” Messonnier said.

The rout in stocks was front-run by a rally in bonds, pushing yields down even further, as investors sought safe-haven investments. Both the 10-year and 30-year Treasury yield hit an all-time low.

All 11 sectors of the S&P were down in Tuesday trading. Airline stocks fell by around 6.8 percent. Shares of United Airlines were down 6.2 percent. Shares of American Airlines were down 8.5 percent, the worst performance for the major U.S. airlines. Delta Air Lines shares were down 5.8 percent. Shares of Southwest Air were down 7 percent.

Shares of cruise lines continued to fall sharply on Tuesday. Carnival Cruise Line shares were down 4.8 percent. Norwegian Cruise Line shares fell 7.5 percent.

Every component of the Dow fell. Visa shares fell by 5.2 percent. J.P. Morgan Chase dropped by around 4.5 percent. American Express shares declined by nearly 6 percent. Shares of Disney were down around 3.5 percent.