The Health and Agriculture ministries are monitoring the avian flu situation in Turkey and have advised the public to avoid poultry and birds if they visit that country. There is little likelihood that an infected bird will arrive here, as bird migration season is over. In any case, the avian flu virus - which has in previous years infected a handful of local birds - has so far not been passed from person to person but only between infected poultry or birds and people in direct contact with them. Meanwhile, Turkey's European neighbors on Wednesday stepped up border checks against bird flu, disinfecting trucks and passing out fliers, while officials said the risk of the disease spreading westward has increased. Preliminary tests indicate the deadly H5N1 flu strain has infected 15 people in Turkey, including two children who have died. So far, however, all the patients appear to have been infected directly by sick birds. Health experts are watching the virus's spread for fear it might mutate into a form easily passed between humans and spark a pandemic. The World Health Organization said, however, that for now it was leaving its global risk assessment of a human pandemic unchanged, after two years. Dr. Marc Danzon, WHO regional director for Europe, said there was no reason for people avoid visiting Turkey. Authorities in Serbia were inspecting the luggage of travelers from Turkey. And in Macedonia, health inspectors were preparing to screen some 3,000 Muslims expected to return via Turkey this week from the annual haj in Saudi Arabia. In Greece, 500 additional veterinary staff were sent to border areas, to eastern Greek islands and to state laboratories to speed up checks and the results of random bird tests, officials said. Cars and trucks entering Greece from Turkey were sprayed with disinfectant, and drivers were handed leaflets explaining how bird flu is spread. "Whatever is humanly possible is being done. The development of the disease in Turkey is not good... We must not panic, and we must not relax," Greek Health Minister Nikitas Kaklamanis said after a ministers' meeting on bird flu. Greece is gathering stockpiles of antiviral drugs aimed at covering five percent of the country's 11 million people. But officials have refused to give other details of emergency plans, including the cost and the number of available hospital beds. "Unfortunately, we cannot carry out border checks in the sky," Kaklamanis said referring to the danger posed by migratory birds carrying the disease. In Bulgaria, Agriculture Minister Nihat Kabil also warned that the risk of a flu outbreak was increasing with westward mass migration of wild birds toward the wetlands in the north of the country. "At these [wetlands]... the number of the white-headed geese - the main carrier of the virus - has recently increased tenfold and is still rising," Kabil told parliament. Authorities in Serbia said they had stepped up inspections of passengers, vehicles and luggage coming from Turkey, and instructed Serbs who have visited that country to report to hospitals to check for flu symptoms. Serbia is a major transit route for Turks traveling to Western Europe. Turkey also has been a popular tourist destination for Serbs in recent years. In Serbia's United Nations-run province of Kosovo, officials said inspections had reinforced a ban on Turkish poultry products in effect since October. Similar, heightened checks were also being carried out in Albania and Cyprus. George Neophytou, head of Cyprus's Veterinary Service, said he was concerned that inspections in the Turkish-occupied north of the island were of poor standard. "From what we've established, testing methods used [in the north] are not so reliable - they are not EU-approved," Neophytou said.