LONDON (REUTERS) - Botswana's Isaac Makwala was cleared to run in the men's 200 metres at the athletics World Championships on Wednesday by the International Association of Athletics Federations (IAAF) which had previously barred him for medical reasons and he celebrated his reprieve by reaching the final.
Makwala was prevented from running in Monday's opening 200 metres heat and Tuesday's 400m final after falling victim to an outbreak of sickness that has hit many competitors.
The 30-year-old, seen as a leading contender in both events, had insisted he was fit enough to race while the sport's world governing body had said he had an infectious disease and needed to be quarantined.
But on Wednesday the IAAF said the quarantine period had ended and Makwala could run in the semi-finals in the evening - provided he first achieved the qualifying time of 20.53 seconds in an individual time trial before the main session.
"Following a medical examination which has declared him fit to compete, we have agreed under our existing rules that assuming he makes the qualification time, he will run in the 200m semi-final round this evening," the IAAF said in a statement.
The IAAF said it made the decision following a written request from Botswana's athletics federation. It said none of the athletes who had already qualified would be expelled to make way for him.
Makwala followed in the footsteps of the United States women's 4 x 100 metres relay team who ran alone against the clock after successfully appealing against their semi-final elimination at last year's Rio Olympics. They went on to win the gold medal.
Urged on by the crowd, he completed his solo attempt in 20.20 seconds, well inside the target, and finished second in his semi-final about two hours later despite running in the inside lane, widely regarded as the most difficult.
"I'm still running with my heart broken. I was ready to run the 400m, that's the race I've been training for, I don't run the 200m very often," he said.
Makwala's saga began when he failed to appear for his opening 200 metres heat on Monday and the IAAF said shortly afterwards that he had been ordered to withdraw by its medical delegate.
On Tuesday, Makwala told the BBC he had been ready to race and was fit and well for the 400m final later in the day. Shortly afterwards, the IAAF withdrew him from that race as well.
Makwala still went to the stadium on Tuesday but when he attempted to go through the dedicated athletes' entrance, an official and security personnel barred his way and he was led away.
Botswana Sports Minister Thapelo Olopeng was among those unhappy at the treatment of Makwala, a national hero.
"The manner in which our athlete was treated has hurt us all, as there was no conclusive evidence of the disease," he said. "Our officials have prepared a report and we have filed our concerns with IAAF."
Several athletes from Botswana, Germany, Canada, Ireland and Puerto Rico have been taken ill over the last few days, with some quarantined and others forced to miss their events.
Competition organisers said on Monday that the illnesses were a result of gastroenteritis, but public health officials said on Tuesday that laboratory tests had confirmed two cases of norovirus among approximately 30 victims.
Norovirus, sometimes called "the winter vomiting bug," is easily spread, partly because the virus can survive for several days outside the body, Britain's National Health Service says.
"The main issue facing the organisers will be one of trying to attain swift containment, which will be pretty challenging due to the nature of the virus," Shirley Kirnon, a lecturer in Infection Control at Birmingham City University, said.
"It is highly infectious. For those affected, symptoms of nausea, vomiting and diarrhoea can occur within a relatively short period of time; approximately 12-48 hours after exposure."