A teammate of the Tour de France defending champion Tadej Pogacar has tested positive for Covid-19, and the team now face a nervous three days to see if others on the team fall sick.

The 33-year-old Norwegian Vegard Stake Laengen, often seen pulling at the front of the UAE Team Emirates train in a headwind, took ill overnight despite testing negative on Thursday morning.

"He reported symptoms of a sore throat late last night," said team doctor Adriano Rotunno.

"The antigen test was positive and it was confirmed by a PCR," he said.

Rotunno expressed concern the virus may have spread within the team.

"We believe he was infected by an outside source, three to five day ago, giving him time to infect other team members," he said outside the team bus at the start line Saturday.

But Rotunno also revealed the extreme measures the team have gone to in order to avoid infection.

"All the riders have their own room, when normally they would share. They also all have their own masseur," he said.

Laengen was withdrawn from the Tour of Slovenia last month when his roommate Mikkel Bjerg tested positive.

Just ahead of the Tour, Matteo Trentin, a key member of Pogacar's team, also pulled out of the race with Covid.

Pogacar leads the race by 31sec from Jonas Vingegaard with Ineos rider Geraint Thomas third, over a minute behind, but there are 14 stages remaining.

Second case 

Laengen is the second rider to be sent home following AG2R's announcement Saturday that their French rider Geoffrey Bouchard had also contracted Covid.

Suffering throughout the seventh stage, the 30-year-old Tour debutant underwent an antigen test, which came back positive.

Bouchard -- King of the Mountains in the 2019 Vuelta a Espana and the 2021 Giro d'Italia -- was immediately isolated from the rest of the team whose tests, including that of his roommate Mikael Cherel, came back negative.

"During the stage, I did not feel well," said Bouchard.

"It's a huge disappointment because we were just getting to my favourite terrain, the mountains.

"It was my first Tour de France and it's sad to end it like this."

AG2R told AFP Saturday "the entire team returned negative tests on Thursday, we have been exemplary in our testing.

"We had riders pull out of the Tour of Switzerland at the end, but cycling as a whole has been exemplary in going through the protocols."

Tour director Thierry Gouvenou said organisers were ready for such an eventuality.

"We saw the figures (of infections) rising throughout France and we were put on red alert during the Tour of Switzerland when 40 riders had to pull out," he said.

Half a dozen riders had to be replaced prior to the start of the Tour de France due to testing positive for Covid.

Backroom members of the teams competing have had to leave due to testing positive with Quick-Step on their third sporting director since it began in Copenhagen last week.