Greta Thunberg, the teenage climate change activist, has revealed that she has self-isolated after showing coronavirus symptoms.
Where a member of a household has displayed symptoms, Boris Johnson, the Prime Minister, has said all residents should self-isolate for 14 days. Elsewhere, foreign governments have issued similar guidance.
Having travelled around central Europe, visiting Brussels and Hamburg to lead school strike events, Ms Thunberg, 17, decided she should stay at home.
She took to social media to urge young people in particular to take the virus seriously, noting that she did not feel particularly ill.
While Ms Thunberg has not been tested for coronavirus, because her home country of Sweden does not currently test for it outside hospitals, she said it is "extremely likely" she has had it.
In an Instagram post, she wrote: "The last two weeks I’ve stayed inside. When I returned from my trip around Central Europe, I isolated myself (in a borrowed apartment away from my mother and sister) since the number of cases of Covid-19 (in Germany for instance) were similar to Italy in the beginning.
"Around 10 days ago I started feeling some symptoms, exactly the same time as my father – who travelled with me from Brussels.
"I was feeling tired, had shivers, a sore throat and coughed. My dad experienced the same symptoms, but much more intense and with a fever. In Sweden you can not test yourself for Covid-19 unless you're in need of emergency medical treatment.
"Everyone feeling ill is told to stay at home and isolate themselves. I have therefore not been tested for Covid-19, but it’s extremely likely that I’ve had it, given the combined symptoms and circumstances.
"Now I’ve basically recovered, but – and this is the bottom line – I almost didn’t feel ill. My last cold was much worse than this! Had it not been for someone else having the virus simultainously (sic) I might not even have suspected anything.
"Then I would just have thought I was feeling unusually tired with a bit of a cough. And this it what makes it so much more dangerous.
"Many (especially young people) might not notice any symptoms at all, or very mild symptoms. Then they don’t know they have the virus and can pass it on to people in risk groups.
"We who don’t belong to a risk group have an enormous responsibility – our actions can be the difference between life and death for many others.
"Please keep that in mind, follow the advice from experts and your local authorities and stay at home to slow the spread of the virus. And remember to always take care of each other and help those in need."
Ms Thunberg initially isolated herself as a precaution having been on trains, but then started to develop symptoms, she added in a video interview with the New Scientist.
"If it wouldn't have been for my father getting it at the same time, and much more intense than me, I might not have noticed it," she said.
She urged people to practice social distancing "whether you feel ill or not", in line with widespread guidance which aims to prevent transmission from person to person.
The Swedish prime minister, Stefan Löfven, has said people have "great individual responsibility" to stop the spread of coronavirus. The country has so far reported 2,286 cases and 36 deaths.