The coronavirus has spread to the Greek island of Lesbos - just 10 miles away from 27,000 migrants living in squalor at a refugee camp.
An unidentified 40-year-old woman has been diagnosed with the killer disease, the island's first case, after having recently travelled to Israel and Egypt.
She was placed in quarantine on Sunday, the public ERT television reported.
Greek authorities have expressed concern over the possibility of the virus spreading on islands such as Lesbos, where thousands of migrants are crammed in overcrowded camps or living rough.
A school, attended by the woman's two children in Plomari, was closed amid fears of an outbreak.
Lesbos is hosting 27,000 migrants and refugees at a reception centre at Moria outside the port capital, Mytilene, the Guardian reported.
The reception is made to house just 3,000 people.
More than 1,700 asylum seekers arrived in Greek islands on the Aegean sea last week, the majority in Lesbos, after Turkey decided to open its borders with Greece.
Turkish President Recip Tayyip Erdogan planned to pressure the European Union to implement what he called an unfulfilled pledge under a previous migrant deal.
Greece's health ministry on Monday reported 11 new coronavirus cases but did not mention Lesbos.
A total of 84 cases have been reported in the country.
Most of the new cases in the country involve a group of pilgrims who visited Israel and Egypt at the end of February, travelling in the same bus.
Greece has banned public gatherings, closed several schools and universities and ordered professional sports events to be held behind closed doors for 15 days beginning Monday.
© Associated Newspapers Ltd.