The Brewers face Wigan on Saturday but only had 12 fit players in training on Tuesday.
Clough said: “We have been hit by a sickness bug the last few days and only had 12 outfield players at training so we are down on numbers with illness and injury. Sickness bugs are hard to contain in football clubs with being in the same dressing rooms, on the same buses and in the same hotels. Once a bug starts going round usually three or four get it. We hope the illness will clear up for Saturday."
Luke Varney (punctured lung), Will Miller (hamstring), Ben Turner (hamstring), Chris O’Grady (calf strain) and Jackson Irvine (groin) are all facing fitness battles.
New signing Varney is the longest-term injury casualty after suffering a punctured lung at Watford.
Clough said: “He spent three nights in hospital. We think it will be four to six weeks but it’s hard to put a timescale on it. It’s when he is comfortable with the breathing aspect of it. It’s bad luck for us but especially for him to get that injury on his debut.
“Will is struggling for the weekend with a hamstring. Ben is hopefully back training this week and is about 50-50.
“Jackson is also 50-50.
“Chris hasn’t trained so far this week and he’s another doubt.”