One is the loneliest number: Botswana's Isaac Makwala crosses the finish line in his heat. Credit:AP

Norovirus. It sounds hideous and sinister, but it's a name for a gastroenteritis-like virus which is, for those who have had the misfortune of the bucket and bowl experience, awful – but not a skin-peeling, sea fleas, flesh-eating misery.

Makwala had apparently up-chucked in the medical rooms only days earlier and so been quarantined for fear that London was revisited by the black plague. On Tuesday, he arrived at the warm-up track for the 400m final and was carried away by organisers as if he was on Monty Python's dray carrying the newly dead. "But I'm not dead!" he protested. "Oh, you will be soon," IAAF organisers shrugged.

When evidence was presented that Makwala was indeed a modern-day Lazarus – not the new striker for Millwall but an athlete who was neither dead nor going away – the IAAF had to consent that due to matters completely out of his control he had not been able to run the 200m heat so they would let him run a heat on his own.

If he could run down lane 7 wearing a pair of Depends and get satisfactorily through his race without smearing either the name of athletics nor the pale lycra pants he was wearing, in 20.53s or less, then he would be allowed to advance.