Scientists also are increasingly worried that the H5N1 strain could mutate into a form easily passed between humans, triggering a global pandemic. 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, said the WHO’s Dr Margaret Chan, citing UN Food and Agriculture Organisation estimates of the toll on farmers.
“Concern has mounted progressively, and events in recent weeks justify that concern,” Dr 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.
In Austria, state authorities said Monday that three cats have tested positive for the deadly strain of bird flu in the country’s first reported case of the disease spreading to an animal other than a bird.
The cats had been living at an animal shelter where the disease already was detected in chickens, authorities said.
In Poland, a third wild swan has tested positive for the H5N1 strain of bird flu, a lab announced. The swan was found dead Saturday in Torun, about 120 miles north-west of Warsaw - the same place where the first two cases were detected.
Dr Chan told over 30 experts in Geneva 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.
WHO says 175 people are confirmed to have caught bird flu, and 95 of them have died.
Global influenza pandemics - as opposed to annual recurrences of seasonal flu - tend to strike periodically. In the 20th century, there were pandemics in 1918, 1957 and 1968.
Bird flu could potentially cause more deaths than those from the global flu pandemics. Because the H5N1 virus is airborne, it is easier to transmit and more contagious than HIV/AIDS, WHO officials said.
Dr Mike Ryan, director of epidemic and pandemic alert and response at WHO, said: “We truly feel that this present threat is likely to stretch our global systems to the point of collapse.”
This is the first time world health authorities have tried to stop a global influenza pandemic before it begins. Dr Chan referred to the spread of severe acute respiratory syndrome, or SARS, as evidence of “how much the world has changed.”
SARS infected 8,000 people, killing 800 of them.
WHO spokeswoman Maria Cheng said experts hope to isolate areas where there is a bird flu outbreak and establish agreements allowing international health authorities to respond quickly, testing viruses and implementing containment measures.
Public health measures to quarantine areas, isolate people or help give antiviral medicine to those infected with bird flu also are on the agenda of the meeting, which ends today.