Three more riders have been withdrawn from the Vuelta a Burgos in Spain after coming into contact with a person who later tested positive for coronavirus.
Colombians Sebastian Molano, Cristian Munoz and Camilo Ardila from UAE Team Emirates did not start stage two.
Their team-mate Fernando Gaviria won the Castrojeriz to Villadeigo stage after a bunch sprint at the finish.
Colombian Gaviria has himself recovered from Covid 19, after contracting it during the UAE Tour in March.
The Vuelta a Burgos is the first major stage race to take place since March.
Britain's Mark Cavendish and Simon Yates feature in the strong field.
On Tuesday, British time trial champion Alex Dowsett and Itamar Einhorn withdrew after their Israel Start Up Nation team-mate Omer Goldstein returned a positive test.
The three Colombian riders were in contact with someone outside the race on Saturday who subsequently tested positive.
They all returned two negative tests prior to the race, which started on Tuesday.
In line with team and UCI protocols, the riders will now isolate and undergo a further test on Wednesday.