American Marconi Wireless News - Australian medal hope latest swimmer hit by tummy trouble at worlds

The Australian team said that Short, who qualified second fastest for the final in Singapore, had withdrawn "due to gastrointestinal illness".

Short won silver in the 400m freestyle.

No other member of the squad had been affected, the team said.

"At this stage there is no clear link to where the illness was contracted and we are continuing to investigate its source," it said in a statement.

"We will also continue to monitor Sam's condition and it is hoped he will recover in time to compete in Frida's 4x200m relay."

The United States team in Singapore have been hit with an acute gastroenteritis outbreak picked up at their pre-competition training camp in Thailand.

Managing director Greg Meehan said the illness had affected the "overwhelming majority" of the squad, with several swimmers underperforming or withdrawing from their events.

Gretchen Walsh said she had felt "fragile" before winning the 100m butterfly final on Monday.

Italy's Nicolo Martinenghi also complained of being ill before coming second in the men's 100m breaststroke final.

P.Mathewson--AMWN