Valencia have confirmed 35 per cent of coronavirus tests conducted on people associated with the club have come back positive.
The Spanish club acknowledged there had been five cases of COVID-19 among first-team players and staff on Sunday, with Ezequiel Garay, Jose Gaya and Eliaquim Mangala all confirming their diagnoses.
Further testing has since led to "several" more confirmed cases within the club, who in the past month – including just last Wednesday – have played two matches against Atalanta of Italy, the European nation worst affected by the pandemic.
Valencia calculate they have a positive test rate of 35 per cent since facing Atalanta in Milan – an area designated as high risk for the virus – on February 19.
A club statement published on Monday read: "Several further tests for the COVID-19 coronavirus among Valencia coaching staff and players have come back positive.
"All cases are asymptomatic and those involved are currently isolated at home, receiving medical assessment and carrying out their scheduled training plan.
"Despite the strict measures adopted by the club after the Champions League game against Atalanta on February 19 in Milan – an area confirmed as 'high risk' by the Italian authorities days afterwards – which included maintaining a distance between the squad and club employees/the general public, these latest results show that the exposure inherent to such matches has caused a positive test rate of around 35 per cent."
With Spain in lockdown, the previous round of LaLiga fixtures were postponed and there will be no games this weekend either.
Spain has reported 9,682 COVID-19 cases, with 342 deaths.