BEIJING — A handful of new human fatalities from bird flu underscore that the H5N1 virus has become entrenched in some countries, such as China, and that it still could mutate and flare into a global pandemic, U.N. officials said Wednesday.
China has reported five deaths from eight cases of bird flu so far this year.
U.N. advisers said that the victims had come into contact with infected poultry in scattered areas of China, and that the virus still wasn't contagious among humans. They cautioned against dismissing the H5N1 virus as a threat to humanity, however.
"We really shouldn't be complacent," said Vincent Martin, a senior technical adviser on avian influenza in China for the Food and Agriculture Organization, a U.N. group based in Rome.
"If it happens, it will be really scary for everybody. The attention has been sort of waning during the years. . . . Infection is still going on. Today, we are seeing people dying of the disease."
The deadly H5N1 strain of avian influenza began to infect humans in late 2003 and has spread to 15 countries, killing 254 of the 407 people who've contracted it.
Hans Troedsson, the chief representative of the World Health Organization in China, said the WHO hadn't changed its risk assessment of bird flu in China after the recent deaths, adding that the virus often spreads more easily in the winter months.
He said the prevalence of fowl in millions of backyards in rural China made eradicating the H5N1 virus difficult.
"The virus is well-entrenched and circulating in the environment," Troedsson said.
The officials, speaking at a forum for foreign correspondents, said "hot spots of infection" for H5N1 virus occurred in China, Indonesia, Vietnam and Egypt, where wild birds — largely shore and aquatic birds — carried the virus, sometimes infecting poultry.
Curiously, the human infections in China this year didn't follow a reported poultry outbreak, and Martin urged Beijing to enhance surveillance to ensure that outbreaks don't go unreported.
Public health experts fret that an influenza A virus, perhaps H5N1, could mutate or re-assort itself genetically to allow human-to-human transmission, becoming a global contagion that could threaten tens of millions of lives. Such contagions occur in cycles.
"It's always at certain intervals, and it's overdue," Troedsson said, adding that the last major flu outbreak occurred four decades ago and was known as the Hong Kong flu.
He said that a worst-case scenario for a flu outbreak would shut down airports worldwide, strain hospitals, severely disrupt food and water supplies, and lead to shortages of anti-viral medications. A best-case scenario might cause only 100,000 deaths, he added.
"We don't know which virus strain is going to do it," Troedsson said. "What's important for us is that governments continue to do their preparedness planning."
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