*EPF507 01/30/2004
U.S. Aiding International Effort to Contain Bird Flu
(Health officials fear virus could trigger human epidemic) (910)

By Charlene Porter
Washington File Staff Writer

Washington -- Millions of poultry in 10 nations have been destroyed to stop the spread of avian influenza in Asia. Eleven human cases of the disease have been reported, resulting in eight deaths. This dangerous flu strain -- designated H5N1 -- has not yet been seen outside Asia, but it is getting serious attention at the U.S. Centers for Disease Control and Prevention (CDC) in Atlanta, Georgia.

"We're taking this very seriously right now and doing everything that we can to make sure that we're offering the best possible support for the World Health Organization (WHO) and others who are combating the problem in Asia," said CDC Director Dr. Julie Gerberding in a briefing January 27. She said CDC is keeping vigil for the appearance of the H5N1 virus in the United States, and beginning processes for development of vaccine candidates and effective diagnostic procedures.

The cases of sickness appearing in people -- so far in Vietnam and Thailand -- all seemed to result from contacts with infected birds, carrying a strain of the virus that has adapted into a form that will cause human illness. The most significant concern is that H5N1 could mutate further into a flu strain that can be transmitted from human to human. If human-to-human transmission were to develop, a new virus to which people have no immunity would be let loose.

That scenario is the epidemiologist's nightmare, and it's one straight from the history books. In 1918-1919, more than 40 million people died from exposure to a previously unknown flu subtype. If a similar situation develops today in an era of globalization and rapid transit, medical experts fear a disease could rampage around the world even more rapidly, taking as many, if not more, lives.

"That is very sobering to us," Gerberding said.

The prospect of a flu strain racing unchecked around the globe is just what international health officials feared a year ago when a new illness began causing deaths first in Asia and then in more and more nations. SARS was dangerous because it had leapt the species barrier from its natural reservoir in animal populations to humans who had no immunity from the disease.

"Eleven out of the last 12 emerging infectious diseases that we're aware of in the world that have had human health consequences have probably arisen from ... animal sources," Gerberding said.

Mass slaughter of poultry is the response to the current threat. The World Health Organization reports January 29 that such action "is the major line of defense for preventing further human cases of H5N1 infection and possibly averting the emergence of a new influenza virus with pandemic potential."

At the same time, WHO warns that workers actually slaughtering the birds run the risk of exposure to the virus and developing an illness. They could become the human conduit for a new virus with the dreaded capability for human-to-human transmission.

The danger mounts when more disease outbreaks are reported, as they were January 30 when China officials announced suspected avian flu in two more provinces and in the densely populated city of Shanghai. The slaughter of poultry is under way within three kilometers of any farm where infection is found in hopes of stopping the chain of transmission, according to press reports.

Stopping disease depends on detecting it in the first place, and that is not a foolproof system. The WHO representative in China said January 30 that weaknesses exist in the surveillance of animal populations, though the world's most populous nation has improved in its capability to track disease in the human population.

In her briefing, CDC's Gerberding cited several difficult factors in looking for disease in animals. "There's a delay in recognizing that there's infection in poultry flocks simply because of the rural nature of that industry and the lack of access to surveillance and laboratory capabilities there to really confirm it," she said. Health officials must recognize the importance of linking disease surveillance systems in humans and animals, she said, noting that U.S. epidemiologists have only recently developed a greater recognition of this as a priority issue.

Developing knowledge, skills and technical facilities is a critical component in achieving a higher level of disease surveillance capability. Gerberding said CDC is working toward that end in both Vietnam and Thailand currently. CDC scientists are part of a WHO team called into Vietnam in response to the current avian flu outbreak. The relationship with Thailand is more longstanding. Gerberding said CDC has been supporting an epidemiological training program in Thailand for 26 years.

"We are involved in the very active surveillance of certain respiratory illnesses in some areas of that country, and have a very robust interaction with the Minister of Health there," she said. In addition, Gerberding said the recently approved federal budget for 2004 also includes increased funding earmarked for international collaborative efforts to improve disease surveillance.

In the face of the immediate situation in Asia, CDC is developing diagnostic test kits in conjunction with WHO and making them available to health practitioners in the field. Further, Gerberding said CDC is working to develop a vaccine candidate to ward off the H5NI strain, which is not quelled by existing vaccines. Still, vaccine development is a complex process that could take months.

(The Washington File is a product of the Bureau of International Information Programs, U.S. Department of State. Web site: http://usinfo.state.gov)

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