Official fears bird flu epidemic
WASHINGTON – The Earth may be on the brink of a worldwide epidemic from a bird flu virus that may mutate to become as deadly and infectious as viruses that killed millions during three influenza pandemics of the 20th century, a federal health official said Monday.
Dr. Julie L. Gerberding, head of the Centers for Disease Control and Prevention, said scientists expect a flu virus that has swept through chickens and other poultry in Asia will genetically change into flu that can be transmitted from person to person.
The genes of the avian flu change rapidly, she said, and experts believe it is highly likely the virus will evolve into a pathogen deadly for humans.
Gerberding made the remarks in a plenary lecture at the national meeting of the American Association for the Advancement of Science.
In Asia, a number of people have died who caught the flu from chickens or ducks. The mortality rate is very high – about 72 percent of identified patients, said Gerberding.
Cases also have been documented of this strain of flu being transferred from person to person, but the outbreak was not sustained, she said.
“We are expecting more human cases over the next few weeks because this is high season for avian influenza in that part of the world,” said Gerberding. Although cases of human-to-human transmission have been rare, “our assessment is that this is a very high threat.”
The avian flu now spreading in Asia is part of what is called the H1 family of flu viruses. It is a pathogen that is notorious in human history.
“Each time we see a new H1 antigen emerge, we experience a pandemic of influenza,” said Gerberding.
In 1918, H1 appeared, and millions died worldwide. In 1957, the Asian flu was an H2, and the Hong Kong flu in 1968 was an H3.
The H1-type of avian viruses has made small appearances in other years but nothing like the H5 rampaging through the birds of Asia now.
“We are seeing a highly pathogenic strain of influenza virus emerge to an extraordinary proportion across the entire western component of Asia,” Gerberding said. “The reason this is so ominous is because of the evolution of flu. … You may see the emergence of a new strain to which the human population has no immunity.”
Study already has shown that the virus can infect cats that can infect other cats, which Gerberding said is “another harbinger” of the possibility of a human pandemic.
A special flu team, organized last year, continues to monitor the spread of avian flu and to analyze the various strains as they appear.