(Close): US shares ended lower with investors unnerved by the first confirmed case of Ebola in the US.
Fears about global economic growth and a stronger dollar also hurt.
The Commerce Department said August construction spending fell by 0.8%, and a report from the Institute for Supply Management indicated a modest slowdown in the manufacturing sector.
The Dow Jones fell 238 to 16,805, the S&P 500 fell 26 to 1,946 and the Nasdaq index fell 71.30 to 4,422.09.
Almost all the 30 stocks comprising the Dow Jones fell. Intel and Johnson & Johnson were both down more than 2%.
Airline stocks fell amid speculation the US Ebola case would mean lower passenger traffic. Delta Air Lines fell 3.5% and United Airlines lost 2.8%.
General Motors gained 1.7% after it said it was aiming for a 9-10% profit margins by the early 2020s.
Cola-Cola was up 0.2% and was the only Dow member to close up after it said it would trim its executive compensation plan.
The New York Times Company leapt almost 10% after it said it would cut costs by shedding 100 jobs, more than 7% of newsroom staff.
Tekmira Pharmaceuticals found itself flavour of the day - it is developing treatment for the Ebola virus and its shares rose 18%.
