Two more Watford players are self-isolating after being in close contact with people who have tested positive for coronavirus, says manager Nigel Pearson.
It is another blow for the club who also have several players, including captain Troy Deeney, staying away from training due to ongoing safety concerns.
"The testing situation is obviously to minimise risk, so for the players and staff who have been in this week statistically they should be a lot safer but it is still a surprise for those who have tested positive," boss Pearson said.
"They're all feeling OK, and likewise for their families as well. That is important for us to make sure that those people - their health is OK.
"In addition to that, we've had a couple more people who have to be in isolation because they've been in close contact with people who have tested positive, even though their own result came back negative.
"I think that shows the types of complications that we've got. Today everybody has been tested again, we were tested on Friday morning, and we await further results over the weekend now.
"It is just something we have got to get used to. We are trying, as everybody will be, to establish what is now a more normal working practice in the circumstances that we have. That is what we have got to work with. But they're OK."
On how many of his squad have been absent this week, Pearson said: "One through testing positive, two more through being in contact with somebody else and the others because they decided not to come in.
"I don't intend to give specific numbers, but we've had several players who have not been available for different reasons this week, but it is what it is.
"We can't do much about that at the moment and hopefully that situation will change in time."
Mariappa had already tested positive and Pearson says he is feeling well and looking forward to returning to training once given the all clear.
He told Sky Sports News: "When I saw him for the test last week, I was sitting in the car park chatting to players as he came past so I had a chance to touch base with most of them.
"He looks exceptionally well and feels very well himself so I think it's an example of how this virus can affect people in different ways.
"He's following the advice and recommendations and isolating for a week. His family are all okay as well. I have no doubts in his case he'll be fine when he comes back in.
"The point about this is there will be people who have the virus and who shake it off easily and some who are more susceptible.
"There are still a lot of unanswered questions. He's disappointed he's not in and we've got other people who are away because they have to self-isolate because of being in contact with people who have been tested positive, and then we have players who have decided they will continue to train on their own."
Pearson says the mood in the camp is positive as Watford prepare to resume their fight against Premier League relegation.
"I've made my position abundantly clear what I do feel. My position as the head coach here is to support my players and staff and we will work towards getting our group of players in the best possible place and we're able to be competitive again," he said.
"We are still very much involved in a relegation battle and we can't drive the political vehicle that's ploughing ahead.
"It's very clear from the government stance they have no intention of slowing down our involvement back in the Premier League.
"I don't like being involved in a propaganda campaign but having read the info that's come our way about 'Stage 2' and all the stuff that's in the public domain about how they want to push it forward.
"It's very clear what the agenda is, but my work mode is very much about getting our preparation right, making sure we're all okay and that when we do return we are able to retain our Premier League status.
"That's really the priority - but not at the expense of people's well-being for sure."
Kabasele: June 12 restart 'impossible'
Watford defender Christian Kabasele believes the potential Premier League return date of June 12 would be "impossible" and action should not resume until later that month.
'Project Restart' is well under way as the English top flight attempts to resume action amid the coronavirus pandemic.
"Nothing has been confirmed yet," said Kabasele. "Personally I follow the news through the media because nothing has been official for the moment.
"We [see] speak about June 12. I think it is impossible because it would be less than three weeks training after a long period without doing anything, it's a risk for us.
"I'm not sure, I don't have any information but I think we are not going to start June 12.
"The most obvious choice for me is the end of June. Like this you have at least four weeks to train with the team if it's possible.
"We will see. For the moment it's a big question mark on this."