A tour guide in Japan who was recently released from a hospital after recovering from the coronavirus has tested positive again, according to reports.
The Osaka woman, in her 40s, was working on a bus with tourists from the Chinese epicenter city of Wuhan when she was confirmed to be infected with the illness on Jan. 29, according to Agence France-Presse.
The bus driver also was diagnosed with the deadly disease.
The woman was discharged from the hospital on Feb. 1 and tested negative for the virus five days later, though she still had a cough that went away a week later.
But on Feb. 21, she returned to the doctor because of a sore throat and chest pain — and tested positive again on Wednesday, according to AFP.
An official in Osaka said the case is the first of a person testing positive for COVID-19 in Japan after apparently being cleared of it.
Cases of second positive tests have already been reported in China, according to Reuters.
Almost 2,800 people have died of the illness, which has infected about 80,000 people worldwide.
“Once you have the infection, it could remain dormant and with minimal symptoms, and then you can get an exacerbation if it finds its way into the lungs,” Professor Philip Tierno of the New York University School of Medicine told Reuters.
He said much remains unknown about COVID-19.
“I’m not certain that this is not bi-phasic, like anthrax,” he said, meaning the illness might recur after appearing to go away.
In Japan, a total of seven people have died of the illness, including four who had been aboard the Diamond Princess cruise ship, according to Reuters.
The number of confirmed cases in the country rose by 16 to 186, in addition to the 704 diagnosed from the ship.