Hong Kong 3-year-old apparently died of chicken flu Alarm lTC spreads

experts rush to study cases

December 15, 1997|By LOS ANGELES TIMES

HONG KONG -- In late March, chickens began dying on three small poultry farms in Hong Kong's outlying New Territories.

Microbiologists determined that the 4,500 dead birds in tiny Lau Fau Shan village succumbed to a particularly virulent strain of avian influenza. Described by one leading American virologist as "chicken Ebola," the virus spreads swiftly, attacks all the cells in the infected bird's body and is nearly always fatal.

On May 11, a 3-year-old boy was hospitalized here with typical flu symptoms -- acute fever, sore throat and raspy cough. Ten days later, the boy died of viral pneumonia and other complications. Then something happened that has excited and frightened health officials around the world: A lab analysis found that the boy was infected with the same virus that killed the chickens -- the first recorded case of a pure bird virus's infecting a human being.

The discovery, which has been followed by at least three more cases here, one of them fatal, has sent scientists from around the world to Hong Kong and has spread alarm throughout the territory, where worried citizens are releasing caged pets and avoiding chicken in their diets.

But while the new virus -- assigned the scientific name H5N1 -- has troubling implications for world health, it also could help solve one of humankind's greatest medical mysteries about how flu viruses mutate and grow, periodically circling the globe in deadly pandemics.

"The most interesting element," said Dr. Kennedy Short-ridge, an Australian microbiologist and flu specialist at the University of Hong Kong, "is that we are having what appears to be an early warning."

This is the first time that disease specialists have been present at the earliest stage of a virulent new flu strain, said Shortridge. Ideally, this would allow scientists to come up with a vaccine in time to keep the flu from sweeping the planet while at the same time teaching them a lot about its origins.

"This is puzzling," said Dr. Daniel Lavanchy, chief of the influenza program for the World Health Organization in Geneva. "For years, we've known that this virus is dangerous in birds, but we'd never seen a human case. We have no explanation yet, but we don't like it when a new virus gets into humans."

The scariest possibility -- although experts feel it is remote because there is no evidence yet of human-to-human transmission -- is that Hong Kong H5N1 represents what scientists term an "antigenic shift" between species.

Some scientist believe similar shifts preceded the 1918-1919 "Spanish flu," which killed 20 million to 40 million people worldwide, as well as the 1957 "Asian flu" that killed 98,000 and the 1968 "Hong Kong flu" that killed 46,500.

Last week, Keiji Fukuda, an epidemiologist with the Atlanta-based Centers for Disease Control and Prevention, lead a team of five epidemiologists from the centers to Hong Kong.

The team came to study the way the virus is contracted. Since the early 1970s, some epidemiologists have theorized that flu is transmitted to people after first infecting birds, then swine.

The theory holds that pigs, uniquely among animals, carry "receptors" for both bird and human flu viruses. If both are present in a pig, they could create a more lethal hybrid virus that can infect humans.

The theory is supported by the fact that the last two major flu pandemics began in China, which has huge numbers of farm-raised poultry and pigs living in close proximity with its 1.2 billion people.

Pub Date: 12/15/97

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