A Japanese tour guide who recovered from coronavirus recently is back in hospital after testing positive for a second time.
The tour bus guide in her 40s was first diagnosed in late January but was released after making a seemingly full recovery.
She contracted the virus after working with China tour groups including those from the city of Wuhan.
Five days after being discharged from hospital she was back again.
She is the first such case in Japan to contract the virus a second time but there have been reports of others in China.
Scientists think the virus can remain dormant in the system for some time.
"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," said Professor Philip Tierno of New York University’s school of medicine.
The Japan government has ordered all schools closed from Monday for at least a month.
The country has more than 180 cases and four deaths, not including those diagnosed and dead from the Diamond Princess cruise ship.
