The MotoGP class at the Grand Prix of Qatar has been cancelled due to travel restrictions imposed to limit the spread of the coronavirus.
With immediate effect, passengers arriving in Doha on direct flights from Italy, or those having been in Italy in the last two weeks, will be taken into quarantine for 14 days.
That would impact several teams and riders and led organisers to cancel practice, qualifying and the race itself, which were scheduled to take place from March 6-8.
A statement on the official MotoGP website read: "Italy clearly plays a vital role in the Championship and in the MotoGP class – both on track and off – and therefore the decision has been taken to cancel premier class competition.
"As the teams and riders of the Moto2 and Moto3 classes were already in Qatar for the three-day official test at Losail International Circuit earlier this week, the races of both categories will be possible.
"The lightweight and intermediate classes will therefore compete in their season opener from the 6th to 8th March. The same will apply to the Idemitsu Asia Talent Cup, which will have two races during the Qatar Grand Prix as originally planned."
The outbreak of the virus continues to have repercussions for sporting events around the world, with a number of Serie A matches postponed this weekend, while Atalanta fans – whose club is from Bergamo in northern Italy – were checked for symptoms as they entered Lecce's Stadio Via del Mare before Sunday's game.
In golf, the Commercial Bank Qatar Masters, which gets under way on Thursday in Doha, is due to go ahead as scheduled, though.
A spokesperson for the European Tour said: "The preparations for each European Tour event are continuing as planned, enhanced by detailed risk assessment and planning re COVID-19, and that includes this week's Commercial Bank Qatar Masters.
"The European Tour will continue to work with the World Health Organisation, each national government and their public health teams and our own medical experts to ensure we have the latest health and safety and travel advice.
"As with all our tournaments, the well-being of players, spectators, staff and everyone involved with our tournaments remains our absolute priority."
In cycling, four-time Tour de France winner Chris Froome and Team Ineos were among those who were allowed to leave their hotel and travel home from the cancelled UAE Tour, but others remained in quarantine in Abu Dhabi following a coronavirus scare.
The final two stages of the UAE Tour, due to take place on Friday and Saturday, were cancelled on Thursday night.
Organisers announced at the time that was due to two confirmed positive tests for the virus among race staff, though cycling's world governing body later said they were "suspected" cases and it emerged on Saturday both individuals first feared to have the disease had tested negative.