Bird Flu’s Ominous Mutation

October 5, 2007 · Print This Article · Email This Post

RoosterBird flu has mutated again, allowing easier human-to-human transmission and increasing the chances of a bird flu pandemic. According to Dr. Yoshihiro Kawaoka of the University of Wisconsin-Madison, a “specific change” has occurred that seems to allow the H5N1 bird flu virus to grow in the upper respiratory tract. While the virus previously didn’t thrive in the human nose or throat due to the higher body temperature of birds (106 degrees F. as opposed to 98.6 degrees for humans), this new mutation replicates well in the upper respiratory tract of humans. Kawaoka thinks that the current H5N1 strain circulating in Africa and Europe has come the closest to being easily transmissible to people. He also says that samples taken recently from birds in Europe and Africa all have the mutation. Kawaoka’s research was published today in the Public Library of Science journal.
Influenza Sign at Naval Aircraft Factory in Philadelphia, Pennsylvania in October 1918It’s not known how many more mutations are needed to make the avian flu virus highly pathogenic to humans. Earlier this year, human-to-human transmission of bird flu was confirmed in Indonesia. The flu, which is constantly evolving, has infected 329 people in 12 countries since it second outbreak in 2003, killing 201 people. The genetic adaptations are of increasing concern, as they come closer and closer to allowing easy person-to-person transmission of the flu. The first bird flu outbreak in humans occurred in 1997 in Hong Kong, when 18 people were infected and six died. At that time, Hong Kong’s entire poultry flock was destroyed, effectively ending the outbreak. The avian-based 1918 Spanish flu pandemic of 1918-1920 had a high mortality rate, killing an estimated 100 million people worldwide, or more than the number of people who died in World War I. About 600,000 Americans died, in the worst epidemic the United States has ever experienced.

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