Officials around the world have responded to the growing coronavirus outbreak by shutting businesses, closing schools and other facilities, banning gatherings and travel, and proposing large-scale financial bailouts to keep slowing economies afloat.

"The coronavirus is a terrible event ... there is no positive to come out of it," the Swedish teenager told the Thomson Reuters Foundation in an online interview.

"But it also shows one thing: That once we are in a crisis, we can act to do something quickly, act fast," said Thunberg, 17, whose solo school strikes for climate action helped spark a global youth climate strike movement.

"Though it must be in a different way to how we have acted in this case, we can act fast and change our habits and treat a crisis like a crisis."

Thunberg wrote in a social media post on Tuesday that she and her father had both shown symptoms of COVID-19 infection after returning from a recent trip to Central Europe.

She had stayed inside and self-isolated for the past two weeks, though she had not been tested for the virus, she said on Instagram, where she has 10 million followers.

"It's extremely likely that I've had it, given the combined symptoms and circumstances," she wrote.

She said her suspected case was mild, which should be a warning to other young people to follow the advice of experts and local authorities, and stay at home.

"Our actions can be the difference between life and death for many others," she said, adding that she had now "basically recovered."

COVID-19 has so far infected nearly 400,000 people globally with more than 17,000 deaths, according to the Johns Hopkins coronavirus resource center.

The youth climate strike movement that Thunberg inspired drew millions onto the streets around the world in 2019.

This year, however, faced with the emerging pandemic, young Fridays for Future climate activists have taken their weekly actions digital, using the Twitter hashtag #ClimateStrikeOnline.

Thunberg urged young climate activists, many now stuck at home as schools close, to help others through the COVID-19 epidemic and to keep up their activism in safe ways.

"First of all, right now, we need to help in any way we can and back up society and people in need," she said.

In figuring out how to deal with climate change, "what we are telling everyone to do is to listen to the experts and listen to the science, and that's what we need to do in this case as well," she said.

Climate activist Greta Thunberg said on Tuesday the swift and far-ranging economic and social shifts being brought in to stem the coronavirus pandemic showed that the rapid action needed to curb climate change was also possible.The virus crisis "doesn't mean we need to let go completely of activism," she added. "We can do it online and at home. We just need to be creative and find new ways."