Ms Rayner, who represents Ashton, Droylsden and Failsworth, said the signs of illness began last night.
"I am now in self-isolation as I have the symptoms of coronavirus they started last night and have gradually got worse," she tweeted.
"I will be quieter than usual but will still be keeping in touch with people as best as I can."
She told others to "keep safe" and to "stay home save lives".
Ms Rayner is the frontrunner in Labour's deputy leadership, which will conclude alongside the leadership race in a few days.
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