A top bird flu expert predicted Tuesday that the H5N1 virus will not reach the U.S. this year via migratory birds, and warned bird smuggling poses a bigger threat for transmitting the deadly disease.
Robert G. Webster, a virologist at the St. Jude Children’s Research Hospital in Memphis, Tenn., said the virus will eventually arrive in the U.S., possibly carried by infected birds illegally brought into the country.
“While wildlife people in the United States are watching for the appearance of this virus, I would suspect that it may not come this year,” he told The Associated Press, adding it has been historically rare for bird flu viruses to reach the Americas from Europe.
“If it doesn’t come this year, don’t relax, because it will eventually come,” said Webster, in Singapore for a two-day conference that is expected to draw leading bird flu experts.
The H5N1 virus began ravaging Asian poultry stocks in late 2003 and has killed at least 113 people worldwide. Most human cases have been linked to contact with infected birds.
Experts fear the virus will mutate into a form that easily spreads from person to person, potentially sparking a global pandemic.
Webster said he is most concerned about H5N1 becoming established in the world’s wild bird populations because most highly pathogenic bird flu viruses usually do not last long in nature. They typically start in wild birds, infect domestic birds and eventually die out.
“This one has broken the rules and gone back from the domestics into the wild birds. Is it going to be perpetuated there as a killer? That’s the million dollar question,” he said. “Will that virus go to the breeding grounds in Siberia and Africa and come back again? If it does, then the chances are eventually it will learn to go human to human.”
Webster’s laboratory has been conducting animal research to help predict how much of the anti-bird flu drug, Tamiflu, people would need to take and for how long if a pandemic strain emerges, said David Reddy, Tamiflu task force leader for the Swiss-based drug maker Roche Holding AG.
“We don’t have a pandemic strain yet, so you can’t say, are you going to need a high dose or a low dose?” he said. “What we can do is construct models so as soon as a pandemic strain arises, we can very rapidly determine what the best approach is with the drug.”
A Tamiflu study is also being carried out on humans to determine the proper dosage and duration for people infected by the current strain. But the results could take a long time to gather because of the relatively few number of human cases, Reddy said.
Learn from the past
Webster, who has researched bird flu for decades, said the spread of the virus to Africa is especially worrying because of the lack of infrastructure as well as political instability and a health system already overrun by diseases like AIDS.
With “all of those things going on in Africa, you could get human-to-human transmission started and not have the opportunity to do anything about it until it’s out of hand,” he said.
John Oxford, a professor of virology at Queen Mary’s University of London, agreed that Africa is a major concern, but said attention should not be diverted from Asia.
He said countries should learn from catastrophes like the Asian tsunami and Hurricane Katrina that warning systems and preparedness plans must be implemented instead of just being discussed.
“They had been warned, but they didn’t take any notice,” he said of the natural disasters. “It’s all very boring for these politicians to have all these scientists knocking at their doors saying, ’You’d better be careful. This is a threat.”’
He said the recreation of the 1918 Spanish flu, which killed up to 40 million people, has allowed scientists a rare chance to compare what happened then to the situation today.
“Are we all running around the world telling people it’s Armageddon and all that’s happened is 100 people have died?” Oxford said. “I see this as like 1916. You have to learn from what happened. You cannot persuade yourself and other people that this is nothing.”