"Avian flu" means any strain of influenza passed on by birds. This
can be any Type A strain of influenza virus. I assume from context
you mean the threatening strains of avian flu in East Asia, usually
referred to as H5N1 influenza.
As with any other case of influenza, H5N1 is usually spread by
inhalation of infected droplets, or by touching surfaces contaminated
by infected droplets and then touching your mouth, nose, or eyes.
So far this strain has been almost entirely limited to waterfowl and
birds sold in open-air markets. There have been isolated cases of
transmission to humans who live or work around the birds. There have
been rare cases of people, infected with the H5N1 flu virus,
transmitting it to others. Most of these have been people involved in
operations culling or killing off infected bird populations, or
medical personnel.
As for likelihood of reaching Europe--there's no firm answer. So far,
there have been very few transmissions to humans from birds, and even
then fewer still transmissions to other humans. However, influenza is
a very unstable virus and can mutate very rapidly. If one strain of
H5N1 virus mutated so as to become easily transmissible to humans and
among humans, it's likely a global pandemic would result. If the
Spanish Flu Pandemic of 1918 is taken as a worst-case scenario,
approximately 2.5% to 5% of all people who get sick could die, which
seems low except that it's much higher than the usual fatality rate
for seasonal flu.
The likelihood of such a mutation appearing is higher if large
outbreaks among birds are not controlled. Large numbers of infected
birds give the virus a greater opportunity to mutate and potentially
become transmissible to humans. If a pandemic strain does arise, it's
almost certain to reach every corner of the world. Again, taking the
Spanish Flu as a worst-case scenario, up to one-fifth of all people
could get sick.
There is no effective vaccine as yet. Because the influenza virus
mutates so rapidly, new vaccines have to be made for each new strain.
For seasonal flu--what one usually gets in the winter--a new vaccine
is made each year based on predictions of which strains will be worst.
In the case of H5N1, the World Health Organization and affiliates are
working on a vaccine for the common strains.
There are two classes of drugs useful for avian flu, one including the
drugs amantadine and rimantidine, and the other including the drugs
oseltamivir and zanimivir. In seasonal flu outbreaks, these drugs
tend to reduce illness by only one day, but are associated with
reducing the worst effects in people who are especially prone to
getting bad complications from the flu, such as older people,
children, and people with suppressed immune systems. Some information
from Vietnam, however, indicates H5N1 may be resistant to amantadine
and rimantidine, leaving only two good drugs.
In the event of a pandemic, every place on Earth that has contact
beyond its own village is likely to be affected. The 1918 Spanish flu
pandemic spread to virtually every country of the world within a year.
Our world is almost certainly more connected than that.
Most of the information given comes from the following websites.
Basic information about the flu comes from my memory, as I am a
third-year medical student. I can supply book citations if need be.
http://www.who.int/csr/disease/avian_influenza/avian_faqs/en/index.html
http://consensus.nih.gov/1979/1979Amantadine019html.htm |
