Turkey has no reason to panic over the bird flu outbreak, a World Health Organization official said Wednesday, urging Turks anew to avoid sick or dead poultry suspected in the rapid spread of the deadly H5N1 strain. "The worst situation is a panic situation. There is no reason to panic," Dr. Marc Danzon, WHO regional director for Europe, told reporters at a news conference with Turkish Health Minister Recep Akdag. Danzon said health officials were doing "everything that is known to maintain and manage this difficult situation." Danzon said there were no signs that the deadly strain, which preliminary tests indicate has infected 15 Turks - including two children who have died - was being transmitted person to person. "There is no transmission from human being to human being through a mutation that could cause a pandemic. We are not there at this point," he said. Health experts have warned of the possibility that H5N1 could mutate into a potent form easily passed between people, triggering a pandemic capable of killing millions worldwide. The WHO said earlier Wednesday that two more people sickened by bird flu in China have died, bringing the total number of humans killed by the disease in that country to five and pushing the death toll worldwide to 78. Turkey's 15 suspected cases in one week is a record for the current bird flu outbreak. WHO so far has confirmed only four of Turkey's 15 reported cases as H5N1, but said it is confident the remaining samples would be positive. If all are confirmed, never before has such a high number of cases been seen in such a short time. Three people died last week, but only two were confirmed to have tested positive. Asked about whether countries should ban or restrict their citizens from traveling to Turkey, Danzon called it "a non-story" and said there was no reason to take such measures. In Turkey, all of the cases appeared to have involved adults or children who touched or played with infected birds. "The people of the country need to perfectly understand that the danger is contact between sick or dead poultry and a human being, especially a child," Danzon said. "This is the key point for the future. This is where we need to pass messages to the population and inform local leaders." European governments, scrambling to avoid the specter of a mutation that could trigger a pandemic capable of killing millions, sprayed trucks from Turkey with disinfectant. In Italy, a consumer group urged the government to impose a ban on travel to Turkey, and in Greece, veterinary inspectors stepped up border checks. Underscoring the vulnerability neighboring countries feel, Bulgaria began issuing its citizens special instructions on how to deal with an outbreak. Turkey's government, anxious to demonstrate to its citizens and the European Union that it was taking decisive action, ordered more than 300,000 fowl destroyed as a precaution. Health officials said Tuesday most of the 70 or so people hospitalized with flu-like symptoms had tested negative for bird flu. "The situation has been taken seriously from the beginning" in Turkey, Danzon said. "The action in the country has been appropriate and the management of this crisis is at the level where it should be and we are satisfied both by the type of action taken by the Ministry of Health and by the possibility of our team to act independently and with transparency," he added. WHO officials said initial investigations suggest there is no change in how the disease is spread, and experts are hoping there may be some differences in the behavior of poultry farming families in Turkey to explain the high number of cases. Another possibility is a change in the virus. Tests were under way, the officials said. The WHO has warned each new human case increases the virus' chances of mutating into a form easily passed from human to human. Authorities distributed leaflets in eastern regions most affected by the outbreak, cautioning people not to touch fowl, while television spots urged people to wash their hands after contact with poultry.