Bird flu: questions and answers
BY MAGGIE Fox, Health and Science Correspondent
A man and a child feed doves in a scenic spot in, China’s Jiangsu
province, The fight against bird flu is serious, said Chinese
Agriculture Minister Du Qinglin on Tuesday. He also demanded the
agricultural departments take all measures to prevent the spread of
bird flu, Xinhua reported. REUTERS
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WASHINGTON (Reuters) - World leaders are moving to try to control a
growing outbreak of H5N1 avian influenza, which is spreading to poultry
flocks in several Asian and European countries. Here are some answers to
frequently asked questions about the disease.
Why are we so worried about H5N1?
The H5N1 strain of avian influenza not only kills chickens quickly,
but it can now infect people. The World Health Organization has
confirmed 126 infections and 64 deaths, with another nine suspected or
locally confirmed cases.
That doesn't sound like very many people.
It isn't - yet. But H5N1 concerns health officials and scientists
because, like all other flu strains, it is steadily changing. This virus
lacks only the ability to pass among people the way ordinary, seasonal
flu does.
If it acquires this transmissibility, it will infect millions of
people within months and it may be more fatal, both because it is so
pathogenic itself and because people do not possess any immunity to it.
When is this likely to happen?
No one can say. It might happen tomorrow, 10 years from now, or
never. It is also possible the mutation process will cause this virus to
lose its dangerous qualities.
So why not bet on the best outcome?
Because health experts agree that a big pandemic of something is
overdue. In the last century there were three major pandemics of
influenza - the 1918 flu, which killed anywhere between 20 million and
100 million people, depending on the estimate, the 1957 flu, which
killed about 4 million, and the 1968 flu, which killed about 1 million.
What can we do?
There is an experimental vaccine, but flu experts say it is unlikely
to be a good match for the H5N1 strain that will eventually emerge.
Using current technology it takes 6 months or more to make a new flu
vaccine and there is no way to predict what the pandemic strain will
look like, so no way to work ahead.
Companies are trying to develop quicker and better ways to make flu
vaccine but their efforts will take several years to bear fruit.
Will the regular flu vaccine help?
No. The seasonal flu vaccine provides no protection against H5N1. But
health officials recommend getting it, not the least because regular
influenza kills up to 500,000 people a year globally in a "normal" year.
What about drugs?
There are four drugs that work against influenza in general -
amantadine and rimantadine, Tamiflu, know generically as oseltamivir,
and Relenza, known generically as zanamivir.
Tamiflu, invented by Gilead Sciences and made and sold by Swiss drug
giant Roche AG, is the main choice. But its effects against H5N1 are not
well known, it must be given early on in the infection to help, and it
is in short supply.
Relenza, made by GlaxoSmithKline and invented by Australia's Biota
Holdings, is considered equally effective but it is inhaled and might
worsen asthma and related conditions.
H5N1 has shown some resistance to amantadine, meaning the virus has
evolved mutations that make the drug less effective. It could also
evolve resistance to Tamiflu and Relenza.
Countries are working to stockpile these drugs but current production
is low and supplies are severely limited.
Surely modern medical practices will help?
In fact, public health around the world is in bad shape. Hospitals
are filled to overflowing now and will not be able to cope with any
serious epidemics. Many experts agree there is no reason to believe an
influenza pandemic today will be less severe than in years past.
How can people protect themselves?
The same way they protect against any respiratory infection - by
regularly washing hands, or using an alcohol-based hand sanitizer, and
by avoiding anyone who is obviously ill.
Influenza viruses are carried in mucus, which people spread in
droplets while talking, sneezing or coughing, or by touching their noses
and mouths and then a surface.
If there is a pandemic, how bad it will be?
This is impossible to predict. But the H5N1 virus appears to be more
similar to the 1918 virus than to more recent pandemic influenza
viruses. That suggests it could affect healthy young adults even more
than the very old and the very young who are usually most vulnerable to
influenza.
It currently has a 50 percent fatality rate, which is exceptionally
high. Seasonal flu usually has about a 0.5 percent fatality rate.
A pandemic could cause widespread panic and disruptions to
transportation, supplies of food, and services. Schools may close for a
time and businesses may be affected as people stay home to care for
children or sickened relatives. |