Joachim Löw has confirmed that seven of his Germany players are showing symptoms of illness in the buildup to Friday’s World Cup quarter-final against France.

Days after Mats Hummels was ruled out of the game against Algeria due to sickness, the Germany manager said the problem seemed to have spread, without naming specific players.

“Seven players are slightly ill with flu symptoms,” said Löw. “It is not that bad at the moment and it could be partly about air conditioning, the travel, temperature differences. I do not want to make a drama of it. We hope the situation will ease.”

The coach Andreas Köpke said the midfielder Christoph Kramer was among those struggling with “slight chills”. Hummels, though, tweeted that he was recovering from his infection, writing he felt “almost back at 100%”, while Lukas Podolski is also likely to be available to face France after recovering from a thigh strain.

Löw, meanwhile, has defended Mesut Özil after criticism in Germany of his performances so far.

“Mesut is extremely important to us,” he said. “The criticism of him is just as incomprehensible as that for Philipp Lahm. Sometimes things get published a little too hastily and I don’t feel the right weight is given to certain things.”

Nevertheless, Löw acknowledged that his side’s performance against Algeria was not a vintage one.

“You can’t always play fantastic football at a World Cup. You’ve just got to leave the field triumphant, and that’s what we did. We have worked hard, both during the preparation in South Tyrol and here in Brazil, and realised what we must improve. It’s only normal that you keep on learning throughout a tournament.”