Health threat reshapes U.S. presidential race

WASHINGTON, March 13 (Reuters) - The U.S. presidential campaign enters a new and uncertain phase on Friday when Democratic front-runner Joe Biden holds his first virtual town hall for Illinois voters after pulling back from in-person campaigning because of the coronavirus pandemic.

Louisiana on Friday became the first state to reschedule voting in the run-up to the Nov. 3 election because of the outbreak. Officials there said they would postpone their scheduled April 4 primary by two months.

Biden's campaign declined to provide details about Friday's online event, scheduled to begin at 4 p.m. CDT (2100 GMT).

On Tuesday, voters in four states go to the polls for the latest of the Democratic nominating contests amid nationwide jitters that have prompted cancellations of many public events.

Biden and his Democratic rival Bernie Sanders, both seeking to challenge Republican President Donald Trump, have taken themselves off the campaign trail for the time being while searching for new and creative ways to connect with voters.

The coronavirus has so far killed at least 40 people and sickened more than 1,600 across the United States, forcing schools to close, professional sports to suspend or end their seasons, and many workers to work from home.

On Thursday, both Biden and Sanders called for a more aggressive response from Trump and the U.S. government.

The town hall Biden will hold on Friday is not entirely unprecedented. During Trump’s impeachment trial in January, when senators running for president were forced to remain in Washington, candidates Amy Klobuchar and Elizabeth Warren held telephone events. Both have since left the race.

Biden has won over much of the Democratic establishment while stringing together wins in such states as Michigan, Texas and North Carolina, giving him a commanding edge in the contest over Sanders.

On Tuesday, the populous states of Arizona, Florida, Illinois and Ohio hold primary contests with a total of 577 delegates at stake. A strong showing could put Biden on an unstoppable path toward nomination at the party's July convention.

Biden and Sanders will participate in a nationally televised debate on Sunday in Washington, held without a live audience out of health concerns, allowing them a final chance to address voters in those states.

Even without traditional rallies, Biden has financial resources at his disposal. With new contributions pouring in, Biden's campaign is running TV ads in Florida, Illinois and Ohio. The campaign has ramped up spending on Facebook ads.

He also is backed by a super PAC, Unite the Country, while another leading Democratic outside group, Priorities USA Action, said this week it would defend Biden against Trump's attacks, with the expectation he will be the nominee.

His candidacy have been bolstered by his familiarity to Democratic voters who know him from his two terms as Barack Obama’s vice president.

(Editing by Scott Malone and Howard Goller)