LONDON -- U.S. distance runner Ryan Hill withdrew from the 5,000-meter final at the IAAF track and field world championship on Saturday after contracting a viral illness.
Hill was due to take on Mo Farah in the Briton's last race at a major championships but was advised by team doctors not to run.
A statement from the USATF, released less than two hours before the race was set to start, said that Hill's illness was "not believed to be related to the norovirus outbreak affecting some athletes and teams in London."
England's public health body has estimated that 40 people connected to the championships have contracted the norovirus.
Anyone reporting the symptoms to event officials has been ordered to spend 48 hours in isolation and prevented from competing until declared fit again.