Saturday, February 28, 2009

Avian Influenza update

I was annoyed to hear a Bird Flu report on our local television news this past week. It referred to a Low Pathogenic strain that poses no risk, Influenza circulates through the avian community, as human forms circulate through the human community. Reporting this not uncommon event gave it more significance than it deserves. As time has passed since the most alarmist coverage, more scientists are reviewing their work and reaching very different conclusions about Bird Flu, such as Bruce Levin, noted below:
Biodefense news tips: Story ideas from the ASM Biodefense Research Meeting

The following news tips are based on presentations at the 2009 ASM Biodefense and Emerging Diseases Research Meeting, February 22-25 at the Baltimore Marriott Waterfront Hotel in Baltimore, Maryland.

IS OUR OBSESSION WITH PANDEMIC BIRD FLU JUSTIFIED? While it is almost a certainty that within the next few decades humanity will experience another influenza pandemic, it may not be caused by the avian influenza strain H5N1 that many scientists believe could be a prime candidate.

"We continue to be aroused and some nearly panicked by the threat of a flu pandemic caused by the avian influenza virus, H5N1. Is this anxiety justified? In the more than 15 years since it was first recognized, this bird flu virus has yet to cause very much mortality in humans or evolve to be readily transmitted between people," says Bruce Levin, the Samuel Candler Dobbs Professor of Biology at Emory University.

Nevertheless, because of the high case mortality of humans infected with H5N1 (sometimes exceeding 90%), pandemic influenza caused by this avian virus has appropriately stimulated a great deal of research on the microbiology, immunology, pathology, virulence, epidemiology and evolution of influenza. It has also contributed to a renaissance of interest in the great influenza of 1918, says Levin. "The next pandemic could well have the potential to kill as many or more people than that in 1918, but we are far better prepared to deal with the next influenza pandemic than we were that of 1918," says Levin. Unlike now, in 1918:·

It was not clear that a virus was responsible for the pandemic ·

There were no vaccines or even ways to develop vaccines to prevent the disease

There were no antiviral drugs to mitigate the course of this disease and reduce the rate of transmission

There were no antibiotics to treat, or vaccines to prevent, secondary bacterial infections that evidence suggests were the major cause of mortality in influenza patients.

The US Geological Survey, which has tracked Bird Flu in migratory bird populations, also finds that the predictions that H5N1 could be carried and transmitted through those routes have turned out not to be the case, as noted here November 24, 2008.

The news is: Bird Flu is not the threat it has been portrayed to be. Pandemic influenza preparedness is worthwhile, as is being prepared for any emergency. But viewing birds as dangerous disease carriers is not scientifically or rationally justified.

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