Manchester United manager Louis van Gaal admits there is a virus in his camp that has already claimed two members of his first team squad.
Van Gaal's side take on Tottenham Hotspur on Sunday (28 December) having tightened their grip on third place with a 3-1 victory over Newcastle United on Boxing Day.
But the United boss will be without Belgian internationals Marouane Fellaini and Adnan Januzaj as a result of the virus that has affected a number of players at varying levels.
"Januzaj is ill. It is a virus that is now running in the air", he said via his club's official website.
"The virus has approached a lot of players, but for him, it was too much.
"Also Fellaini... I think it is the Belgium virus! Will he be ready for Spurs? No he is ill.
"Fellaini and Adnan are not ready."
Januzaj's absence also fuelled suggestions the 19-year-old will leave Old Trafford on loan during the January window with Everton and Real Sociedad touted as possible destinations.
However, van Gaal has recently ruled out the possibility of the young Belgian leaving the club.
United are also likely to be without record signing Angel di Maria after the Argentine missed the victory over Newcastle with a pelvic problem.
Di Maria suffered the problem during training on Christmas Eve and his manager was unable to provide a return date.
"It is not a muscle injury," van Gaal said. "It is more the pelvis does not have the right relationship with the leg."
He added: "We will have to wait and see for the analysis."
Di Maria, 26, only returned to van Gaal's starting XI in the 1-1 draw with Aston Villa on 20 December after a three-week absence with a hamstring tear.