Bath have closed their training ground with all players and staff isolating at home after the club returned a number of positive coronavirus tests.
The contact tracing process is under way and an additional round of testing will take place on Thursday.
The club posted on Twitter: "This morning, our training ground at Farleigh House has been closed after a number of players and staff returned positive results following the weekly PCR COVID-19 testing programme."
The training ground is being deep cleaned in an effort to halt the outbreak uncovered by Monday's tests.
"This is an anxious time for us all and the mental as well as physical health of our people and their families is our priority," director of rugby Stuart Hooper said.
"Our planned training sessions have been cancelled and those able to train from home will now do so.
"My team and I are focused on doing all we can to be ready to play our up-and-coming fixtures, but I must reinforce that I will not allow the health of our people to be compromised."
Due to the cancellation of the final two rounds of the Champions Cup group stage, Bath's next fixture is not until Friday week when they face Bristol at Ashton Gate.
A decision on whether that match can take place will be made in conjunction with Premiership Rugby next week.
Bath have already had two games cancelled this season – against La Rochelle and London Irish – but both were due to outbreaks of coronavirus at other clubs.
The players and staff who have tested positive and those traced as contacts of those positive cases will isolate for a minimum of 10 days.
"Our immediate focus is taking care of our people and stopping the spread of the virus," Bath chief executive Tarquin McDonald said.
"We are in regular communication with Premiership Rugby and Public Health England as we manage the situation. We will return to training but only when it is safe and appropriate to do so."