Suspected cases of norovirus were identified after an outbreak at the offical hotel of the athletes and staff at the ongoing IAAF World Athletics Championships in London.
Athletes with symptoms including diarrheoa and vomiting began presenting last week with the illness apparently centred around one of the official hotels.
After Botswana's Isaac Makwala was pulled from his 200 metres heat due an onset of gastroenteritis at a team hotel on Monday, Public Health England (PHE) revealed the following day roughly 30 people had fallen ill and two cases had been confirmed as norovirus following laboratory testing. The International Association of Athletics Federations (IAAF), the sport's world governing body, had announced that he had been withdrawn "on the instruction of..."
The hotel added: "We have followed strict hygiene protocol, ensuring that those affected are not in contact with other guests and all public areas have been thoroughly sanitised".
German triple jumper Neele Eckhardt was among the first to show signs of illness, collapsing last week but recovering in time to compete in her event, reaching the final but finishing last.
He had still been hoping to be cleared to race in Tuesday's 400m final, before the IAAF's medical delegate withdrew him from that as well.
It led the team to re-distribute 30 more athletes who arrived in London this week to avoid the hotel where the outbreak started.
"Those affected have been supported by both team and LOC [Local Organizing Committee] medical staff, in addition we have been working with Public Health England to ensure the situation is managed and contained".
A number of other athletes staying at the same hotel also have gastroenteritis, including the Ireland 400m hurdler Thomas Barr.
"My whole year has been focused on the world championships".