US STOCKS-Major indexes end down, but well off session lows

(Corrects "inflation" to "disinflation" in quote in paragraph 6)

* Russell 2000 index ends 1 pct higher

* S&P 500, Nasdaq briefly turn negative for the year

* Indexes off: Dow 1.1 pct, S&P 0.8 pct, Nasdaq 0.3 pct

By Caroline Valetkevitch

NEW YORK, Oct 15 (Reuters) - U.S. stocks fell on Wednesday on continued worries about weak global demand, but managed to close well above session lows that briefly pushed the S&P 500 and Nasdaq into negative territory for the year.

Small-caps and energy shares, which have been among the market's weakest performers, provided some of the late-day support, with the Russell 2000 index ending up 1 percent and the S&P energy index up 0.4 percent.

Adding to the day's worries, a second nurse in Texas tested positive for the Ebola virus, a week after Thomas Eric Duncan, the first Ebola patient diagnosed in the United States, died.

The day's losses threatened to wipe out 2014 gains for the S&P 500 and Nasdaq, with the S&P 500 down more than 3 percent at its low. The Dow industrials fell further into the red for the year, down for the fifth consecutive session.

The S&P 500 is now down 7.4 percent from its Sept. 18 record closing high, and is up just 0.8 percent for the year.

"If you look at the lows of the day, maybe we've put in a little bit of a trading bottom here. But I don't think it makes these concerns about aggregate demand and disinflation go away ... that's really what's weakening the market," said David Joy, chief market strategist at Ameriprise Financial in Boston.

The Dow Jones industrial average fell 173.45 points, or 1.06 percent, to 16,141.74, the S&P 500 lost 15.21 points, or 0.81 percent, to 1,862.49 and the Nasdaq Composite dropped 11.85 points, or 0.28 percent, to 4,215.32.

Options activity has spiked along with the market's slide. Total options volume at the close on Wednesday was 33 million contracts, the busiest day since Aug. 8, 2011, according to Trade Alert.

(Editing by Nick Zieminski)