The Giro d'Italia lost six more cyclists, four of them from former race leader Remco Evenepoel's team, on Wednesday owing to positive Covid tests taking the total of withdrawals due to the virus to 15 since the race began on May 6.
Race favourite Evenepoel had withdrawn late on Sunday due to a positive test and despite the race organisers implementing stricter rules on Monday Covid continues to affect the peloton.
"Soudal Quick-Step is disappointed to announce that four more riders from its Giro d'Italia squad have tested positive for Covid-19 and will leave the race," read a team statement.
"Following the positive test of Remco Evenepoel on Sunday, a further round of tests were made on the riders and staff that remained in Italy, with Jan Hirt, Josef Cerny, Louis Vervaeke and Matteo Cattaneo unfortunately unable to continue."
Their withdrawals leaves just three members of the team in the race – Belgian rider Ilan Van Wilder is the best-placed, 19th some 12 minutes and seven seconds adrift of the overall leader Geraint Thomas, winner of the 2018 Tour de France.
"We will continue to monitor and implement our testing protocol on the three riders and staff that remain at the race," said team doctor Toon Cruyt in the team statement.
The two other cases were both Italian riders, Andrea Vendrame and Stefano Gandin.
Evenepoel and the others were not obliged to withdraw due to a positive test – it is at the team's discretion whether a rider carries on or not as the Covid health protocol has been dropped.
Evenepoel's withdrawal had sparked the race organisers to take extra measures.
"In the light of the latest developments concerning positive test results on some riders, the organisers of the Giro d'Italia informs that wearing a facemask will be compulsory in all areas of contact with the riders," said a race statement.
The statement said those areas include team buses and those parts of the start and finish zones of each stage that it supervises.
Wednesday's 11th stage is one made for the sprinters, a flat 219km ride from Viarregio to Camaiore.