Wall Street stocks tumbled again early Thursday, joining a sell-off in most global bourses on fears the coronavirus will grow into a significant international health crisis.

About 15 minutes into trading, the Dow Jones Industrial Average was down 2.2%, or about 600 points at 26,353.01. The blue-chip index has fallen for the last five days.

The broad-based S&P 500 slid 2.5% to 3,040.13, while the tech-rich Nasdaq Composite Index shed 2.9% to 8,723.22.

The losses came after U.S. public health officials confirmed a coronavirus case in California, the first affliction of unknown origin.

In Japan, Prime Minister Shinzo Abe called for school closures to prevent the spread of the illness, while French President Emmanuel Macron warned the country is "facing a crisis, an epidemic that is coming."

Markets have been rattled by the prospect that lockdown measures such as those employed in China will become more widespread, denting global growth and producing a "nesting" impulse in the consumer-driven U.S. economy.

Goldman Sachs on Thursday slashed its 2020 forecast for U.S. earnings, estimating that it now expects flat earnings in 2020 and lower growth in 2021.

"Our reduced forecasts reject the severe decline in Chinese economic activity in (the first quarter), lower end-demand for U.S. exporters, supply chain disruption, a slowdown in U.S. economic activity, and elevated uncertainty," Goldman said.