Investors around the globe stepped up their retreat from stocks and many commodities, reflecting intensifying fears that a viral outbreak in China will deliver a setback to the outlook for world economic growth.

The Dow Jones Industrial Average posted its fifth consecutive daily decline, dropping 453.93 points, or 1.6%. The S&P 500 also declined 1.6%, its first drop of more than 1% since October.

Meanwhile, the yield on the benchmark 10-year Treasury note fell to 1.605%, its lowest level since October, a signal investors are eschewing risk as they reconsider an outlook that just recently had been brightening. The Cboe Volatility Index, which measures expected moves in the S&P 500 index, also climbed to its highest level since October.

“It’s probably too early to determine the impact to global growth from the outbreak of this virus,” said Allen Bond, portfolio manager at Jensen Investment Management. “The impact on global growth is probably the key uncertainty.”

Concern about the coronavirus intensified as the tally of infections jumped over the weekend. The virus has infected more than 4,500 people and killed at least 106, mostly in China’s Hubei province. It has spread to other countries including the U.S., Japan and South Korea, and public-health officials have warned that it is growing more contagious.