"The last two weeks I've stayed inside," she captioned the post. "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 ten days ago I started feeling some symptoms, exactly the same time as my father - who traveled with me from Brussels. I was feeling tired, had shivers, a sore throat and coughed," Thunberg added. "My dad experienced the same symptoms, but much more intense and with a fever."
In a plea to her millennial and Gen-Z social media followers, Thunberg emphasised that she "almost didn't feel ill" as her last cold was much worse than her latest illness.
"Had it not been for someone else having the virus simultaneously I might not even have suspected anything," she stressed. "Then I would just have thought I was feeling unusually tired with a bit of a cough."
In a bid to encourage others to take self-isolation seriously, the environmental activist concluded: "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."