LONDON (REUTERS) - Wayde van Niekerk retained his world 400 metres title in dominant fashion on Tuesday (Aug 8) as he stormed to victory in 43.98 seconds but there was almost as much interest in the empty lane alongside him where Botswana's Isaac Makwala should have been.

South African Van Niekerk, the Olympic and defending champion and world record holder, ran a controlled race and was even able to ease down over the final strides as he secured the first half of what he hopes will be a 400/200m double.

Steven Gardiner of the Bahamas was a clear second in 44.41 and 20-year-old Abdalelah Haroun of Qatar blasted through at the end to snatch bronze in 44.48 Makwala, third fastest in the year this season, was scratched from the race earlier on Tuesday having also been withdrawn from Monday's 200m heats after vomiting before the race.

He insisted he wanted to run but IAAF officials ruled him out and refused him entry to the stadium amid a swathe of nanovirus and gastroenteritis cases that have affected about 30 athletes from a selection of countries.

Fred Kerley had scraped into the final as a fast loser but finished last as the United States failed to medal in the event for only the second time since the championships began in 1983.