Ms Dorries, the first MP to test positive, said she had taken all the advised precautions after finding out and has been self-isolating at home.
This comes as a sixth person died from the virus in the UK, which has a total of 382 cases.
The latest person to die was a man in his early 80s who had underlying health conditions.
Meanwhile, Manchester City’s Premier League match against Arsenal on Wednesday has been postponed as “a precautionary measure” because of the outbreak.
A number of Arsenal players are in self-isolation after coming into contact with Olympiakos owner Evangelos Marinakis, who tested positive for the virus.
The government will unveil its first Budget later, amid growing fears about the impact the outbreak will have on the UK economy.
Chancellor Rishi Sunak has pledged the NHS will get “whatever resources it needs” during the crisis, while he is also expected to unveil measures to boost the self-employed and small businesses who are left out of pocket.
Meanwhile, NHS England said it was scaling up its capacity for testing people for the infection, with the number of cases set to rise.