Brazil's Rousseff pulls ahead in election poll

Rousseff would win the runoff by 47.7 percent of the votes against 38.7 percent for Silva, widening her lead from the one-point advantage she had in the previous survey by polling firm MDA last week.

In first-round voting, scheduled for Oct. 5, leftist incumbent Rousseff has 40.4 percent voter support and environmentalist Silva 25.2 percent. That compares with 36 percent for Rousseff and 27 percent for Silva in the previous MDA poll. Support for centrist candidate Aecio Neves has risen to 19.8 percent from 17.6 percent last week.

If no candidate wins an outright majority in the first round on, the election will be go to a runoff between the top two vote-getters on Oct. 26.

The MDA poll commissioned by the transport industry lobby CNT surveyed 2,002 people between Sept 27-28 and has a margin of error of plus or minus 2.2 percentage points.

(Reporting by Anthony Boadle; Editing by Meredith Mazzilli)