A resurgence of coronavirus in Greece and its Mediterranean neighbor Israel have taken both countries by surprise and threaten to put a damper on a much-anticipated return to normalcy just as the summer tourist season begins in earnest. Greece registered more than 10,000 positive cases a day in the three 24-periods leading up to Friday and Israel’s “coronavirus czar,” Salman Zarka, said that hospitals across the country were reopening their designated coronavirus wards due to the spike in Covid-19 cases.