The 62-year-old is the first British politician to have contracted the virus, which has infected more than 118,000 people worldwide and caused more than 4,200 deaths.
In a statement, Ms Dorries said: “I can confirm I have tested positive for coronavirus. As soon as I was informed I took all the advised precautions and have been self-isolating at home.
Download the new Independent Premium app
Sharing the full story, not just the headlines
“Public Health England has started detailed contact tracing and the department and my parliamentary office are closely following their advice.
She later tweeted: “Thanks for so many good wishes. It’s been pretty rubbish but I hope I’m over the worst of it now. More worried about my 84-year-old mum who is staying with me and began with the cough today. She is being tested tomorrow. Keep safe and keep washing those hands, everyone.”
The under-secretary of state for health and social care’s diagnosis comes as the number of people to have tested positive for the virus nationwide has risen to 373, the second largest day-on-day increase since the outbreak began.
Meanwhile, the virus has claimed six lives in the UK – the latest, a man in his early eighties with an underlying health condition who died at Watford General Hospital.
Ms Dorries, who represents mid-Bedfordshire in the Commons, was among those to have helped draft the government’s response to the epidemic – which is expected to hit its peak within the next fortnight.
It is unclear how much she may have interacted with senior government officials before becoming unwell – however The Times reported Ms Dorries attended an International Women’s Day reception with Boris Johnson at Downing Street, as well as constituency meetings.
Writing on Twitter, health secretary Matt Hancock said: “Really sorry to hear Nadine has tested positive for coronavirus. She has done the right thing by self isolating at home, and both NHS and PHE staff have been brilliant. We all wish her well as she recovers.
“I understand why people are worried about this disease. We will do all we can to keep people safe, based on the best possible science.”