UPDATE 1 — Bolsonaro's lead over Lula narrows ahead of Brazil runoff, Datafolha poll shows

(Updates with details, context in bullets 3-7) SAO PAULO, Oct 15 (Reuters) — Brazilian Senator Flavio Bolsonaro continues to slightly lead President Luiz Inacio Lula da Silva heading to the October 25 election runoff, but the gap has narrowed, a Datafolha poll showed on Thursday. The senator, the eldest son of former President Jair Bolsonaro, would receive 47% of the vote compared with 45% for the president, according to the poll. Last week, a Datafolha poll showed the younger Bolsonaro leading Lula 49% to 45%. The poll's result still represents a technical tie as the margin of error is plus or minus 2 percentage points 6% of the respondents said they would cast a blank vote, and undecided voters made up 2%, the poll showed In valid votes, which exclude blank votes and undecided voters, Bolsonaro leads Lula 51% to 49% Datafolha surveyed 2,520 people between October 13-14 The younger Bolsonaro surprisingly led Lula in the first-round vote earlier this month (Reporting by Fernando Cardoso in Sao Paulo; Editing by Andre Romani) ((mailto:fernando.cardoso@thomsonreuters.com;)