Bird-flu pandemic threat seen waning

Bird-flu cases have dropped sharply in Europe and have not caused the human calamity expected in Africa, health officials report.

Meanwhile, Vietnam, which has the world’s largest death toll from avian influenza at 42, has been free of the disease in both people and poultry all this year. Thailand, which has had 14 deaths from avian flu, has not had a human case since mid-2005, nor one in poultry in six months, according to the United Nations.

No one in the international public health community is stating categorically that the threat of a human pandemic of bird flu has been averted. But they acknowledge aggressive control measures undertaken by nations such as Vietnam, Thailand, Egypt and Nigeria have made the bird-flu problem, to date, far less devastating than was anticipated.

“Only time will tell when this virus is going to burn out. It may have gone, but we don’t know,” said Dr. Richard Slemons, an associate professor of veterinary preventive medicine at Ohio State University, who is a specialist in bird flu.

One thing that looks encouraging, Dr. Slemons said, is that H5N1 — the bird-flu virus that’s been causing great public concern since late 2003 because it has afflicted 208 persons in 10 nations, killing more than half of them — first appeared on the scene nearly 10 years ago in Hong Kong, but has never caused a pandemic.

“Eighteen people were infected, and six died during an outbreak of H5N1 in Hong Kong in 1997. It was the first time a bird-flu virus jumped from birds to humans. So this has been going on for 10 years, and a human pandemic resulting from human-to-human transmission hasn’t happened,” Dr. Slemons said in a telephone interview.

“But this does not mean it won’t,” he added.

Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, said yesterday he was gratified to learn that an Indonesian outbreak did not involve human-to-human transmission, as some officials had initially feared.

Dr. Fauci said it appears increasingly likely that eight members of an Indonesian family who were thought to be sickened by bird flu — six of them died — were afflicted after handling infected chickens or the birds’ fecal matter. World Health Organization officials had been alarmed by the possibility that the Indonesian “cluster” of cases might have been transmitted by human-to-human contact, a mutation that could trigger a pandemic.

Dr. Fauci says he thinks it would “not be appropriate to say the bird-flu threat is over, as long as the virus is still circulating in chickens and infecting people.” Under those circumstances, he said, it potentially “could still evolve” into a virus that could harm more people by spreading from person to person.

However, he said the achievements of countries such as Vietnam, Thailand, Egypt and Nigeria in successfully combating H5N1 “show that with the proper attention, we can get control of this virus.”

There have been encouraging — but qualified — comments this week about the improved avian-flu situation from international health officials.

Scientists had feared the disease would spread with the spring migration of wild birds. But WHO spokeswoman Maria Cheng told USA Today those fears have not materialized.

At a meeting on avian influenza Monday in Uppsala, Sweden, Zsuzsanna Jakab, director of the European Center for Disease Prevention and Control, told Agence France-Presse: “Now the number of bird-flu cases, at least in the European region, has gone down. This means migratory birds have gone, but we should be prepared. They will come back in autumn.”

A precautionary program Europe implemented, which separated commercial birds from other birds, has been effective, said Dr. Slemons of Ohio State.

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