Dutch title contender Steven Kruijswijk, his Jumbo-Visma team and the entire Australian cycling team Mitchelton were on Tuesday pulled out of the ongoing Giro d'Italia stage race after positive Covid-19 tests.
Team Jumbo-Visma's Kruijswijk, who finished third in the 2019 Tour de France, returned a positive test along with a second rider, Sunweb's Australian Michael Matthews.
The Mitchelton team said they had been notified of four positive results for "staff members" after tests conducted on Sunday.
"Upon receiving the results, Mitchelton-Scott immediately withdrew its team from the race and will focus on the health of its riders and staff and their safe movement to areas of quarantine," the team said in a statement before Tuesday's 10th stage of the race.
Mitchelton general manager Brent Copeland added: "As a social responsibility to our riders and staff, the peloton and the race organisation we have made the clear decision to withdraw from the Giro d’Italia."
Copeland said those who tested positive "remain asymptomatic or with mild symptoms" and they would now undergo a period of quarantine.
Mitchelton had already been hit by Saturday's withdrawal of Briton Simon Yates, their lead rider and race contender who became the first rider to test positive for Covid-19 at a Grand Tour.
Yates, who was 21st in the standings ahead of Saturday's stage with overall victory still potentially within his grasp, had tested positive for coronavirus after developing a mild fever on Friday.
- 'I just feel fit' -
The announcement of Team Jumbo-Visma's complete withdrawal followed that of Kruijswijk, another blow for the Dutchman, a top-five finisher in all three Grand Tours who missed this year's Tour de France with a knee injury.
"Within the team we take a lot of measures to avoid contamination," said the 33-year-old, who showed no symptoms of having contracted the virus.
"I just feel fit. I can’t believe I got it. It is a very big disappointment to get this news. It is a pity that I have to leave the Giro this way."
And Team Sunweb added that the now-quarantined Matthews was also "currently asymptomatic, feels healthy".
"All other riders and staff returned a negative test and at this stage, no other team member displays symptoms of Covid-19," Sunweb said.
"The team will continue to closely monitor all within their bubble, operating with as much discipline as possible, doing the maximum it can."
Giro organisers said they had carried out a total of 571 tests on Sunday and Monday.
Mitchelton aside, two other staff members, one each from Team AG2R-La Mondiale and Team Ineos Grenadiers, also tested positive for Covid-19 and "were entrusted to the respective teams' doctors who ordered their isolation measures", organisers said.
The positive tests throw into doubt the future of the three-week Giro, which now features 21 teams and is scheduled to finish in Milan on October 25.
Despite Tour de France director Christian Prudhomme testing positive and having to self-isolate, last month's Grande Boucle went through to the finish line with not one rider testing positive, just four staff members from four different teams.