Senior minister among those being tested after meeting Nadine Dorries before she was diagnosed

A cabinet minister is among a growing number of people who have self-isolated after coming into contact with the health minister, Nadine Dorries, before she tested positive for coronavirus.

A government source confirmed on Wednesday evening that the senior minister was among those in voluntary isolation awaiting the results of tests, but would not confirm who it was.

Junior health minister Ed Argar, who does not attend cabinet, is also self-isolating after having dinner with Nadine Dorries on Thursday night.

Others self-isolating include the Labour MP Rachael Maskell, at least two students and staff from a catering college who served Dorries at a Downing Street reception, and her Mid Bedfordshire constituency chairman.

Hundreds of others with whom Dorries came into contact in London and her constituency are being contacted by health officials.

Dorries, 62, has been in self-isolation at her home in Gloucestershire since Saturday and is worried about her 84-year-old mother, who is staying with her. A member of her staff has also contracted the illness and her parliamentary and ministerial offices are both sealed off, as are some corridors leading to them.

On Wednesday evening, Dorries explained she had felt weak and tired on Thursday last week – the day of the Downing Street reception – and the first symptoms began on the Friday morning, as she took part in a constituency surgery.

Dorries tweeted: “For clarity, on Thursday I felt weak and tired but didn’t start with the first symptoms (cough) until 10.45am Friday morning.”

Her confirmation raises questions over why she did not stop working immediately. Staff at the club where the surgery took place said she was there from around 10.45am-12.15pm and it is understood that she went on to a pub.

Dorries added that the Public Health England tracers whose job is to track people she had come into close contact with had been “amazing”. Dorries also paid tribute to the community testing nurses who had been “so kind” to her mother.

Dorries was last in the House of Commons on the afternoon and evening of Wednesday 4 March. She spoke in a debate on health inequalities and twice went into the “no” division lobby to vote. She would have been close to hundreds of MPs.

Matt Hancock, the health secretary, told the Commons on Wednesday that parliament would not close.

On the morning of Thursday 5 March, Dorries was in her office in the House of Commons, where she had a meeting with Maskell to discuss mental health issues.

The York Central Labour MP said there was no indication Dorries was ill. They did not shake hands but sat about 2ft apart for half an hour. Once the news broke that Dorries had the virus, Maskell rang NHS 111 and was advised to self-isolate for 14 days since her contact with the minister.

Maskell remains asymptomatic but has compiled a list of those people with whom she has been in contact in case she contracts the virus. She said: “I’m fine but frustrated that I can’t get on with my work.”

Facebook Twitter Pinterest The Flitwick Club in Bedfordshire. Photograph: John Robertson/The Guardian

On Thursday afternoon, Dorries was among leading figures from business, science and sport who attended a reception for international women’s day in Downing Street.

The prime minister took part in a panel discussion with Olympic medallist Dame Kelly Holmes. It is understood Boris Johnson had no close contact with Dorries at the event, and has no symptoms, meaning he does not need a test. A Downing Street spokesman said he “wished Nadine Dorries a speedy recovery”.

The event was attended by 50 girls who are due to make their GCSE choices and guests enjoyed salmon cream cheese tarts, teriyaki skewers and baked vanilla cheesecakes provided by female students from the Westminster Kingsway College.

At least two students and a member of staff have self-isolated but are not showing symptoms. One of those at the reception said some had received conflicting advice over whether to self-isolate by NHS 111. “It is a bit confusing and worrying,” she said.

On Friday 6 March Dorries visited a club in the Bedfordshire town of Flitwick for a constituency surgery and saw about a dozen people.

Steve Scott, president of the Flitwick Club, said Dorries spent around an hour and a half there. The club took advice from NHS 111 after hearing about her condition and is cleaning all surfaces and keeping the committee room where the surgery took place off-limits.

Facebook Twitter Pinterest Nadine Dorries spoke in a debate on eating disorders in Westminster Hall last Thursday. Photograph: Parliament live

Outside the front door, a sign informed customers that the meeting took place in the committee room, and not in either of the bars. “We advise anyone who is feeling unwell to contact 111 for further advice,” it added.

Steven Dixon, chairman of the Mid Bedfordshire Conservative Association, met Dorries after she left the club and is now self-isolating for seven days. “It’s a precaution and seems sensible,” he said. The association is writing to all members to alert them to the possibility of infection.

Q&A How can I protect myself and others from the coronavirus outbreak? Show Hide The World Health Organization is recommending that people take simple precautions to reduce exposure to and transmission of the coronavirus, for which there is no specific cure or vaccine. The UN agency advises people to: Frequently wash their hands with an alcohol-based hand rub or warm water and soap

Cover their mouth and nose with a flexed elbow or tissue when sneezing or coughing

Avoid close contact with anyone who has a fever or cough

Seek early medical help if they have a fever, cough and difficulty breathing, and share their travel history with healthcare providers

Advice about face masks varies. Wearing them while out and about may offer some protection against both spreading and catching the virus via coughs and sneezes, but it is not a cast-iron guarantee of protection Many countries are now enforcing or recommending curfews or lockdowns. Check with your local authorities for up-to-date information about the situation in your area. In the UK, NHS advice is that anyone with symptoms should stay at home for at least 7 days. If you live with other people, they should stay at home for at least 14 days, to avoid spreading the infection outside the home.

Dorries ate lunch at the nearby Jolly Coopers pub in Flitton. The landlord, who asked not to be named, said he was worried about the potential impact her visit could have on business. Dorries ate in a private room, and staff said she did not appear to have any symptoms.

The landlord said: “We have consulted with Public Health England and are closely following their advice. We remain open as usual and are continuing to follow a rigorous and regular cleaning schedule.”

In the constituency, people were keen for more information. “We all want to know where’s she’s been – so we know where to avoid,” said one woman in the town of Shefford. “We’ve been carrying on as normal here, but something like this brings it home to you.”

In London, Chris Bryant, the former deputy leader of the Commons and Labour MP for Rhondda, said parliament should not close – as was mooted last week as part of coronavirus contingency planning – but could consider restricting visitors.

Meanwhile, union representatives said parliamentary staff should be allowed to work from home.

• This article was amended on 12 March 2020. We described Chris Bryant as a former deputy speaker in the Commons, when he was a former deputy leader in the Commons. This has been corrected.