Election officials in Louisiana have postponed the state's Democratic primary scheduled for 4 April amid fears of the coronavirus, marking the first US election to change course under the outbreak and setting a precedent for other states as voters prepare to head to the polls to select the nominee to face Donald Trump.

The state will hold the election on 20 June.

Louisiana Secretary of State Kyle Ardoin said despite the state's resilience against hurricanes and other disasters, "the threat we face from the Covid-19 virus is an unprecedented threat and unlike any we have faced."

He pointed to Louisiana law provisions that provide for "extraordinary measures" in the event of a disaster. An emergency suspension or delay in elections an be called "due to the possibility of emergency" before or during regularly scheduled elections "to ensure maximum participation in the electoral process" and "minimise exposure to the danger" during a state of emergency.

Secretary Ardoin issued a recommendation to Governor John Bel Edwards to authorise the order.

The announcement arrives just days before four states hold their Democratic primaries on 17 March as Joe Biden and Bernie Sanders compete for the party's nomination.

On Tuesday, Arizona, Florida, Illinois and Ohio are still scheduled to hold their elections.

There are more than 1,400 confirmed cases throughout the US, including at least 41 deaths. Louisiana has identified 33 cases of the flu-like respiratory illness in the state.

Democratic primaries: Who won where?







18 show all Democratic primaries: Who won where?

































1/18 Alabama: Biden wins Joe Biden: 41 delegates Bernie Sanders: 7 delegates Michael Bloomberg: 1 delegate Reuters

2/18 Arkansas: Biden wins Joe Biden: 17 delegates Bernie Sanders: 9 delegates Michael Bloomberg: 5 delegates AFP/Getty

3/18 California: Sanders wins Bernie Sanders: 179 delegates Joe Biden: 127 delegates Michael Bloomberg: 15 delegates Elizabeth Warren: 5 delegates AP

4/18 Colorado: Sanders wins Bernie Sanders: 20 delegates Joe Biden: 9 delegates Michael Bloomberg: 9 delegates Elizabeth Warren: 1 delegate AFP/Getty

5/18 Iowa: Buttigieg wins Pete Buttigieg: 14 delegates Bernie Sanders: 12 delegates Elizabeth Warren: 8 delegates Joe Biden: 6 delegates Amy Klobuchar: 1 delegates Reuters

6/18 Maine: Biden wins Joe Biden: 11 delegates Bernie Sanders: 9 delegates Elizabeth Warren: 4 delegates AFP/Getty

7/18 Massachussetts: Biden wins Joe Biden: 37 delegates Bernie Sanders: 29 delegates Elizabeth Warren: 25 delegates AP

8/18 Minnesota: Biden wins Joe Biden: 38 delegates Bernie Sanders: 27 delegates Elizabeth Warren: 10 delegates Reuters

9/18 Nevada: Sanders wins Bernie Sanders: 24 delegates Joe Biden: 9 delegates Reuters

10/18 New Hampshire: Sanders/Buttigieg tie Bernie Sanders: 9 delegates Pete Buttigieg: 9 delegates Amy Klobuchar: 6 delegates EPA

11/18 North Carolina: Biden wins Joe Biden: 66 delegates Bernie Sanders: 36 delegates Elizabeth Warren: 2 delegates Michael Bloomberg: 2 delegates AFP/Getty

12/18 Oklahoma: Biden wins Joe Biden: 21 delegates Bernie Sanders: 13 delegates Michael Bloomberg: 2 delegates Elizabeth Warren: 1 delegate Reuters

13/18 South Carolina: Biden wins Joe Biden: 39 delegates Bernie Sanders: 15 delegates Getty

14/18 Tennessee: Biden wins Joe Biden: 33 delegates Bernie Sanders: 18 delegates Michael Bloomberg: 10 delegates Elizabeth Warren: 1 delegate Reuters

15/18 Texas: Biden wins Joe Biden: 111 delegates Bernie Sanders: 102 delegates Michael Bloomberg: 10 delegates Elizabeth Warren: 5 delegates Reuters

16/18 Utah: Sanders wins Bernie Sanders: 12 delegates Joe Biden: 2 delegate Michael Bloomberg: 2 delegates AFP/Getty

17/18 Vermont: Sanders wins Bernie Sanders: 11 delegates Joe Biden: 5 delegates AP

18/18 Virginia: Biden wins Joe Biden: 66 delegates Bernie Sanders: 31 delegates Elizabeth Warren: 2 delegates AFP/Getty

Louisiana's municipal elections set for 9 May have also been postponed. They will be held on 25 July.

The state has 3 million registered voters, including more than 1.2 million Democratic voters, the state's largest party-affiliated electorate. Its presidential primary elections are closed, meaning only people registered with their party can vote in respective primaries.