Giro d'Italia leader and favourite Remco Evenepoel had to withdraw from the race on Sunday after testing positive for coronavirus.
Evenepoel had won the day's individual time trial to reclaim the leader's pink jersey.
But his Soudal Quick-Step team later announced that the world champion had returned a positive test for COVID-19 after the end of Sunday's ninth stage.
"I am really sorry to be leaving the race," Evenepoel said.
"As part of the team's protocol, I took a routine test, which unfortunately was positive.
"My experience here has been really special and I was looking forward to competing over the next two weeks. I can't thank enough the staff and the riders who sacrificed so much in preparation for the Giro. I will be cheering them on over the next two weeks."
The rest of the team and staff were tested and were all negative.
Evenepoel had also won the opening time trial in dominant fashion and had led the Giro until the end of the fourth stage.
The 23-year-old Belgian had a 45-second lead over new race leader Geraint Thomas, who rides for Ineos Grenadiers. Primož Roglič, who was considered Evenepoel's strongest challenger, was two seconds further back.
Evenepoel, who won the Spanish Vuelta last year, has had miserable luck in Italy.
He crashed out of the 2021 Giro, the only time he has competed in the Italian Grand Tour. That was Evenepoel's first race back after a serious accident the previous year that left him with a broken pelvis after a crash sent him flying off the side of a bridge.
That also happened in Italy, in the Tour of Lombardy.
AP
