Scientists also are increasingly worried that the H5N1 strain could mutate into a form easily passed among humans, triggering a devastating global pandemic, though it has not yet undergone such a transformation. However, WHO said, it already is unprecedented as an animal illness in its rapid expansion.
Since February, the virus has spread to birds in 17 countries in Africa, Asia, Europe and the Middle East, the WHO's Dr. Margaret Chan was quoted as saying, citing U.N. Food and Agriculture Organization estimates of the toll on farmers.
"Concern has mounted progressively, and events in recent weeks justify that concern," Chan, who is leading WHO's efforts against bird flu, told a meeting in Geneva on global efforts to prepare for the possibility of the flu mutating into a form easily transmitted among humans.
Speaking to more than 30 health experts in Geneva, Chan emphasized that the agency's top priority was to keep the deadly H5N1 strain of bird flu from mutating.
"Should this effort fail, we want to ensure that measures are in place to mitigate the high levels of morbidity, mortality and social and economic disruption that a pandemic can bring to this world," she said.
U.S. health officials revealed today Monday that they have authorized the development of a second vaccine to combat the deadly virus, which already is believed to be changing. The U.S. government has several million doses of a first bird flu vaccine based on a sample of virus taken from Vietnam in 2004. The virus is believed to have evolved since then, health officials said.
Meanwhile, in Austria, three cats have tested positive for the deadly strain of bird flu in that country's first reported case of the disease spreading to an animal other than a bird, government authorities said today. The cats had been living at an animal shelter where the disease already was detected in chickens, authorities said.
Poland announced that the infected swans were found dead Thursday in Torun, about 120 miles northwest of Warsaw. Samples were being sent to Britain for further tests.
Russia reported that about a half a million domestic and wild birds in southern regions have died since Feb. 5, and 350,000 more have been killed by authorities to stem the disease.
Representatives of the ministries of agriculture from Black Sea countries of Romania, Bulgaria, Turkey, Ukraine and the Republic of Moldova, met yesterday in Bucharest to identify common methods of action to combat the dissemination of the bird flu. They agreed to Romania's proposal to establish in Tulcea, located near the Danube delta an international center to research cross-border diseases.
According to the Romanian Minister of Agriculture, Gheorghe Flutur, Romania has already taken the necessary steps to obtain funds from the European Union for the development of this project, the investment being estimated at several millions of Euro.
"We have taken the first steps with the EU, so we hope to set up the Centre before autumn," declared Flutur, pointing out at the same time the need to collect as much information as possible about the H5N1 virus.
The five delegations voiced their availability to strengthen collaboration in combating bird flu, including a joint communication strategy among the veterinary services from the five countries and to establish a common network to monitor the migrating birds. Specialists from these countries would also meet periodically to analyze the evolution of the disease.
The United States has allocated some $1.25 million dollars to Romania to fight bird flu, with more cash to come, the U.S. ambassador to Bucharest revealed.
Nicholas Taubman said the Washington should increase the money to Romania in the next few months to help reduce the economic impact of avian influenza.
"Our two governments will continue to work together to contain the virus, and to prepare for a possible pandemic that is being discussed by scientists and health professionals worldwide," ambassador Taubman told reporters Monday at the Institute for Animal Health in Bucharest.
A laboratory in Kyiv, Ukraine, on Saturday confirmed the bird flu virus in birds of the Odessa zoo, according to the laboratory's director, Artur Abramov.
"This is the same virus as that one registered in the Crimea last December,' he said, acknowledging that the disease has crossed from Ukraine's peninsula to the mainland.
Last December 170,000 domestic poultry in the Crimea was killed by the H1N5 strain.
According to the latest WHO figures, the H5N1 strain has killed at least 95 people since 2003, mostly in Asia, and devastated poultry stocks.