Shares tumbled across Wall Street as news that a patient had been diagnosed with Ebola in Texas spooked investors and left airline shares in particular under pressure.
The benchmark Dow Jones index fell more than 240 points - or 1.4 per cent -in late afternoon trade, while the CBOE Volatility index, also known as Wall Street's fear gauge, rose 5 per cent.
Delta and Southwest airlines were both down nearly 4 per cent.
“African travel isn't a huge part of the travel industry, but it does seem like some parts of the industry are likely to be disrupted from this,” said Mitch Rubin, at RiverPark Advisors in New York, told Reuters.
Although losses were seen across most sectors, stock markets in the US remain close to all-time highs they reached last month.