Washington – A flu virus that has killed millions of birds in Asia now has appeared in birds in Europe, but the World Health Organization (WHO) reports that Turkey and Romania have mounted aggressive responses to destroy flocks infected with H5N1.

In a WHO telephone briefing from Geneva October 17, health officials predicted that the virus could appear in other neighboring nations, which have become increasingly watchful since confirmation of the first European appearance of the virus October 13. (See related article.)

“There’s no question that we will expect further outbreaks of avian disease in different countries,” said Dr. Michael Ryan, from WHO’s Department of Epidemic and Pandemic Alert and Response.

Asia is still the place where the greatest opportunity exists for the virus to cross the species barrier and become a disease that easily is passed among people.

Asians are more likely than Europeans to have domestic poultry in and around their homes, experts say, increasing the chances for exposure to the virus in bird droppings or mucus.

“It’s compressed and concentrated here more than anywhere else,” said Alejandro Thiermann of the World Organisation for Animal Health (OIE), in an interview with Reuters in Hanoi, Vietnam.

Thiermann was a member of a U.S.-U.N. delegation that toured several Southeast Asian nations in mid-October, raising governments’ awareness about the dangers of H5N1 and its potential to set off a human influenza pandemic that could cause millions of deaths.

In some nations where officials have heightened awareness of the possibility of pandemic, plans are being made to build drug stockpiles, test human vaccines and develop contingencies in case of widespread illness that might disrupt workplaces and manufacturing and economic activity.

Since a pandemic is most likely to begin in Asia, Thiermann said, concern about appearance of the virus in Europe should not distract from an effort to help Southeast Asian nations combat further disease in birds to prevent emergence of a disease that will pass easily among humans.

WHO has confirmed 117 human cases of H5N1 infection in four Asian nations, resulting in 60 deaths. Because access to medical care is poor in some rural areas and cases may go undiagnosed, the human count could be higher.

No human cases have appeared in Europe.

U.S. Health and Human Services Secretary Michael Leavitt has been in Southeast Asia since October 9, getting a firsthand look at conditions that could give rise to pandemic influenza (See related article.)

While there, he signed agreements with the governments of Cambodia and Laos, pledging U.S. aid and assistance to establish stronger systems for tracking and containing disease.

In an interview with CNN while in Laos, Leavitt said attention to disease in that region today will protect the entire world in the future.

“You can think of the world as a vast forest that's dry and susceptible to fire. If there's a spark -- that is to say, there's a virus that is transmittable human to human -- if we get there soon enough, we're able to stomp it out, just like you are with a spark in a forest fire,” Leavitt said.

“But if it's allowed to fester for a period of time,” he added, “then it begins to grow and soon it's uncontainable.”

The United States is contributing both funds and expertise to assist in disease surveillance and detection in Southeast Asia.

For more information on U.S. and international efforts to combat avian influenza, see Bird Flu.