An American couple who vacationed on the now-quarantined Diamond Princess cruise ship together could be at risk of returning home alone.

Rebecca Frasure has been in isolation in a Tokyo hospital away from her husband, Kent, since Friday when she was diagnosed with the novel coronavirus that has reached epidemic levels in China and become a global health crisis.

The Oregon resident told CNBC her heart "just sank" when she found out she had contracted the disease on the docked vessel.

"I didn't know what to do. I didn't know what to say," said Rebecca Frasure, explaining that she had a minor cough but no fever.

"I'm not allowed to leave my room and I'm not allowed to interact with anybody else," she said in a video that aired on the network's "Outbreak" special report on Wednesday evening.

Kent Frasure, who tested negative of the disease, remains cordoned alone in the cabin he previously shared with his wife. He will be there at least until the mandatory 14-day quarantine is lifted next Wednesday.

The ship is moored at a Yokohama port near Tokyo as Japanese Ministry of Health officials try to prevent the deadly virus from spreading to the island country.

"We didn't have a goodbye kiss just 'cause we didn't really know what was going on," Kent Frasure said in a separate video call with CNBC.

"We Facetime regularly and message each other quite a bit," he added.

The Frasures were two of 3,700 people on board the Princess Cruise ship, a subsidiary of Carnival Corp., that was placed under quarantined last week. At the time, 10 passengers tested positive for the virus. That number has since grown to almost 220. Diamond Princess is now on day nine of its standstill.