The Mexican had been forced to stay in self isolation away from the track on Thursday following an inconclusive test result for COVID-19. However, a follow-up test confirmed he was positive and carrying the virus.
Speaking in a video message posted on Twitter, Perez said he does not know where he picked the virus up from, having followed all protocols during a quick visit to see his mother in Mexico after the Hungarian Grand Prix.
"I am extremely sad," said Perez. "It is one of the saddest days of my career. The amount of preparation that we put into the weekend, to be 100 percent ready for it. I knew I had a great car underneath me and the team have done a fantastic job.
"I'm really sad that this happened, but this shows just how vulnerable we all are with this virus."
Perez revealed that he had taken a private plane back home to Mexico last week to see his mum, who had been recovering from injuries sustained in an accident.
"I follow all the instructions from the FIA, from my team," he said. "After Hungary I took a private plane to go to Mexico, to see my mum for two days because she had a big accident. So as soon as she left hospital. I was able to see her. And then I came back to Europe. Same way, all the protocols in place.
"I don't know from where [I caught it]. I have no symptoms at all. So it just shows how vulnerable we are on this.
"I want to thank all my fellow drivers for all the support that they've given me. My team. The authorities. The fans. Certainly tough moments for me at the moment, but I'm sure I will come back stronger from this."