Organisers of the World Athletics Championships have confirmed a number of athletes have contracted gastroenteritis within one of the official hotels ©Getty Images

Organisers of the International Association of Athletics Federations (IAAF) World Championships have confirmed a number of athletes have contracted gastroenteritis within one of the official hotels for the event here.

This includes Botswana's Isaac Makwala, forced to withdraw from the 200 metres heats before they took place tonight.

Others affected include Irish 400m hurdler Thomas Barr, who was due to compete in the semi-finals but pulled out this morning.

"Tons of cases" of the sickness bug in the Canadian team which is participating at the Championships have been reported.

Both the Irish and the Canadian squads are staying at the Guoman Tower Hotel.

insidethegames understands some of the athletes affected have been quarantined in a bid to stop the illness spreading further.

Gastroenteritis is usually brought on by a bacterial or viral stomach bug and causes diarrhoea and vomiting.

"According to IAAF medics I am apparently suffering from food poisoning which has affected several other athletes,” Makwala, who is one of the favourites for gold in the 400m, wrote on Facebook. 

Barr is reportedly one of 12 athletes to have been struck by the bug.

Irish 400m hurdler Thomas Barr pulled out of the semi-finals today due to being struck by the bug ©Getty Images
Irish 400m hurdler Thomas Barr pulled out of the semi-finals today due to being struck by the bug ©Getty Images

"I'm gutted to have to withdraw from today's semi final," said Barr, who was third at the Diamond League race in Oslo in June.

"I wasn't feeling great yesterday evening and later in the night I was hit with a bad bout of gastroenteritis.

"My whole year has been focused on the World Championships. 

"The support yesterday was just brilliant and to not be able to go out and compete today for Ireland is beyond disappointing."

London 2017 have not confirmed the exact amount of cases but have insisted they have been working with health authorities to "ensure the situation is managed and contained".

"There have been a number of cases of gastroenteritis reported by team members residing within one of the official team hotels for the World Championships," a statement from London 2017 said.

"Those affected have been supported by both team and Local Organising Committee medical staff, in addition we have been working with Public Health England to ensure the situation is managed and contained.

"As a result, further advice and guidelines have been issued to team doctors and support staff - standard procedure for such an occurrence where a number of teams are occupying championship accommodation."