An American woman who tested positive for coronavirus has revealed she has no symptoms.

More than 1,300 people have died after contracting Covid-19 coronavirus but Rebecca Frasure from the United States does not appear to be unwell.

Frasure told Checkpoint in a video interview from isolation in a Tokyo hospital that she tested positive for the virus while on board the Diamond Princess cruise ship.

The ship is docked in Yokohama and all passengers on board are quarantined for 14 days. Frasure's husband is still there.

"I never really felt unwell, I had a little bit of a cough when they told me," she said.

"When I got here I had a bit of a fever, but all of that has normalised and I have no symptoms."

She is not being treated with any medication, but simply seeing out the illness while being monitored in isolation at the hospital.

"Doctors and nurses who come in, they have like a plastic gown or apron covering their scrubs, a mask, a face shield, gloves, they do that every time they come in.

"They're just checking vitals - temperature, lungs, blood pressure, heart rate, and they do that a few times a day.

"I am going to be tested later on today for the virus - it's a two-step process. I'll be tested today and tomorrow, and I'll have to wait for those results."

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Frasure's husband is still testing negative she said. 

"I'd like it to stay that way… just waiting till we can be reunited."

She said there's no indication why she contracted the virus and her husband did not.

"It's just the luck of the draw. I'm just lucky like that, I guess."

If Frasure's latest tests show negative results, she will be free to go and will wait in the area until her husband is free from the quarantined cruise ship.

"I feel perfectly healthy. So it really came as quite a shock that I have this. I expected it to be way more severe," she said.

"So it sounds like that is the case for the majority of the coronavirus 'sufferers'.

"A lot of them don't experience or exhibit a lot of symptoms, it's really those specialised age groups who are most at-risk that develop the extreme symptoms."

Frasure is relaxed about the ordeal.

"This is just a blip on the radar and in hopefully a couple of weeks, a month, a year, it'll all be a distant memory."