Health minister and Conservative MP Nadine Dorries been diagnosed with coronavirus, the BBC reports.
Ms Dorries, the first MP to test positive, said she had taken all the advised precautions after finding out and had been self-isolating at home.
It comes as a sixth person died from the virus in the UK, which has a total of 382 cases.
Ms Dorries, the MP for Mid Bedfordshire, said in a statement that Public Health England had started tracing people she had had contact with, and the department and her parliamentary office were closely following its advice.
The 62-year-old, who began her career as a nurse, later tweeted that it had been “pretty rubbish but I hope I’m over the worst of it now”.
But she added she was worried about her 84-year-old mother who was staying with her and began to cough on Tuesday.
It is not known how many meetings Ms Dorries had attended at Westminster or in her constituency in recent days.
The Department of Health said she first showed symptoms on Thursday of last week – the same day she attended a Downing Street event hosted by the prime minister – and had been self-isolating since Friday.