Prime Minister Costas Karamanlis and the leader of the main opposition PASOK party, George Papandreou, yesterday exchanged frosty letters, each essentially accusing the other of inadequate response to the threat of swine flu, as five tourists were quarantined on a cruise ship in the main port of Piraeus with symptoms of the H1N1 virus. In a letter to Papandreou yesterday afternoon, Karamanlis accused the opposition leader of «scaremongering» and attempting to exploit the serious issue of swine flu «to score political points.» The premier was responding to a letter he had received earlier in the day from Papandreou, accusing the government of having no serious plan for tackling the possible spread of the swine flu pandemic in Greece. «All these shortfalls and this complacency create the danger of a pandemic of mild symptoms developing rapidly, with unpredictable consequences on citizens’ health,» the letter said. Meanwhile, five tourists on a cruise ship arriving in Piraeus from Turkey were quarantined in their cabins on the ship after displaying symptoms of the virus. The remaining 3,387 passengers and 1,196 crew members were evacuated. Late last night some reports indicated that the five had been found to be suffering from a simple flu virus and not H1N1 but the reports were not confirmed. More than 520 cases of swine flu have been recorded in Greece but experts believe the real number of affected citizens to be much higher. PASOK’s spokesperson Giorgos Papaconstantinou yesterday suggested that the government had concealed the scale of the spread of swine flu in Greece, quoting officials at the European Center for Disease Prevention and Control as ranking Greece «fourth among European countries as regards the number of cases and second as regards the number of cases per capita.» Thousands of Greeks are said to have stocked up on face masks and vaccines for pneumococcus, a virus that causes pneumonia and meningitis in children. According to experts, this vaccine would be ineffective against H1N1, for which a vaccine is expected to be available in the fall.