In the event of a major virus outbreak (Bird-Flu etc.) what kind of
widely available consumer breathing protection would adequately
protect somebody from the threat of airborne virus transmission.

In other words, are the simple white filters that are commonly seen in
Japan enough to protect the user, or is something more required. If
more is required, what would fit the bill.

Some kind of web link to the product that would fulfill the
requirements would be appreciated

Hi, I hope I can provide the information you need.

The 1918-19 flu probably killed close to a hundred million directly
worldwide (WHO says more than 40 million and 675,000 just in the U.S.
which had a population of only 100 million then); it was also an avian
flu variety; and only had a mortality rate of about 2.5%.

The current avian flu variety (H5-N1)has an initial mortality rate of
about 50-70% (at leat 40% even with early detection and full modern
medical care) so if, as usual, the mortality rate comes down by 90
percent as it mutates, it will be still be extremely dangerous. Also,
there are already several known cases in humans which doesn't appear
to have any connection with chickens - no one knows if they caught it
from another human.

So, perhaps it is something to be concerned about as the World Health
Organization says.

We simply won?t know until a mutation starts to spread in humans, if
it does. But pandemics come along every so often and there is little
defense against them - by definition - if there were, they wouldn't
become pandemics.

As for the filters, you can't block a virus with any filter you could
draw air through just using lung power for an extended period but the
good news is that the flu is mostly transmitted by touch or aerosol
droplets which are much larger than a virus, that is, you pick it up
on your hands and then touch your face, or breathe in when someone
sneezes or coughs - exercise care in public places and stay out of
crowds if it hits - that is the best protection. Simple masks do stop
moisture drops from spreading through the air and can help prevent the
person wearing one from spreading infections - they just don't
anything to prevent you catching a virus. There are special masks
which are recommended to avoid infection (see below.) You can buy
these locally at most medical supply houses, perhaps even your local
drug store - just ask for a mask qualified for influenza (it doesn't
have to be specific for "bird flu".)



The Dept. of Labor OSHA guidelines are found at:
http://www.osha.gov/dsg/guidance/avian-flu.html

?Most human influenza infections are spread by virus-laden respiratory
droplets that are expelled during coughing and sneezing. Influenza
viruses range in size from 0.08 to 0.12 micrometers.6 They are carried
in respiratory secretions as small-particle aerosols (less than 10
micrometers in diameter).?

So, the masks you wear to protect yourself from aerosol flu infection
only need to block water droplets about 10 microns in size, much, much
larger than the actual virus and this is possible.

Other countries have been taking this far more seriously than the U.S.
and there is a UK site
http://www.lawson-his.co.uk/scripts/products.php?cat=Avian%20Influenza%20Protection

which says the 3M model 8835 mask would provide good protection ? this
is not the thin dust mask you see people wearing all the time, it is a
fairly large mask but reasonably priced around $25 U.S. for a box of
5.


The U.S. Food and Drug Administration site which is most useful is:
http://www.fda.gov/cdrh/ppe/fluoutbreaks.html

You can find a list of FDA approved devices at:
http://www.accessdata.fda.gov/scripts/cdrh/devicesatfda/

The real authority in this country is the CDC
http://www.cdc.gov/flu/

You can purchase these masks without a prescription, even over the
Internet, but be certain you are getting the real thing, not some
fake. (There is a lot of fake Tamiflu being sold now.) For now there
is no panic about these masks so there is no big black market for
fakes yet but get a brand name from a reputable supplier.

Each winter I like to check the Flue Activity map at 
http://www.cdc.gov/flu/weekly/fluactivity.htm
simply because I would rather avoid catching the flu if it isn?t difficult.

The international information is at
http://www.cdc.gov/flu/weekly/intsurv.htm

The CDC Avian Influenza site is
http://www.cdc.gov/flu/avian/

The WHO site (which I consider much superior) is
http://www.who.int/csr/disease/avian_influenza/avian_faqs/en/index.html

This is what the WHO has to say about the subject in general,
?Influenza pandemics are remarkable events that can rapidly infect
virtually all countries. Once international spread begins, pandemics
are considered unstoppable, caused as they are by a virus that spreads
very rapidly by coughing or sneezing. The fact that infected people
can shed virus before symptoms appear adds to the risk of
international spread via asymptomatic air travellers.
The severity of disease and the number of deaths caused by a pandemic
virus vary greatly, and cannot be known prior to the emergence of the
virus. During past pandemics, attack rates reached 25-35% of the total
population. Under the best circumstances, assuming that the new virus
causes mild disease, the world could still experience an estimated 2
million to 7.4 million deaths (projected from data obtained during the
1957 pandemic). Projections for a more virulent virus are much higher.
The 1918 pandemic, which was exceptional, killed at least 40 million
people. In the USA, the mortality rate during that pandemic was around
2.5%.
Pandemics can cause large surges in the numbers of people requiring or
seeking medical or hospital treatment, temporarily overwhelming health
services. High rates of worker absenteeism can also interrupt other
essential services, such as law enforcement, transportation, and
communications. Because populations will be fully susceptible to an
H5N1-like virus, rates of illness could peak fairly rapidly within a
given community. This means that local social and economic disruptions
may be temporary. They may, however, be amplified in today?s closely
interrelated and interdependent systems of trade and commerce. Based
on past experience, a second wave of global spread should be
anticipated within a year.
As all countries are likely to experience emergency conditions during
a pandemic, opportunities for inter-country assistance, as seen during
natural disasters or localized disease outbreaks, may be curtailed
once international spread has begun and governments focus on
protecting domestic populations.?

If (when) a pandemic does strike, government agencies are recommending
the following
? avoid sick people
- wash your hands often and use the alcohol-based hand cleaners
- prepare your household by stocking several day?s supply of food and water.

There is a basic guide at
http://www.metrokc.gov/HEALTH/prevcont/pandemic-flu.htm#protect

All government publications say you don?t need to stockpile Tamiflu,
but take that with a grain of salt since there isn?t any available to
buy anyway and the government is rushing to stockpile as much as
possible to give out to first responders.

As for vaccine protection, it will take a year or more to produce a
vaccine in quantity (after the flu starts to spread among humans) and
it is grown in chicken eggs -guess what happens to chickens and egg
production? The isolated ?safe? flocks for vaccine production are very
limited in size.

So, the bottom line is, if it spreads to the human population and
mutates into an easily spread infection, an avian flu pandemic COULD
be extremely deadly.

But there is simply no way to predict if this will or won?t happen,
only that some flu pandemic will occur in the near future ? it may be
a very mild flu, or it may be a very dangerous variant of H5-N1.

You don?t need to fear eating chicken, even infected birds if properly
cooked ? according to the WHO, the H5-N1 virus is killed in normal
cooking (no pink parts and no runny egg yolks.)
 
Just so you know, I have had an epidemiology course (several) and
worked as an emergency management planner. Until recently I was a
first responder.

Don't panic, but do make sensible plans, the WHO recommends strict
travel limitations be imposed if it hits so you might want to alter
vacation plans IF, and only IF there are reports of it spreading in
humans.

I hope this provided the information you were seeking.

This is a plausable threat but there are things you can do to prepare.

---

Clarification of Answer by siliconsamurai-ga on 06 Jan 2006 07:20 PST

Not really a clarification, more of an update - we got some very
serious news yesterday when we learned that 4 members of a family in
Turkey had most likely contracted H5N1 (still waiting for the lab
tests) but certainly some varient of bird flu.

Three have already died, the first bird flu related deaths outside of
east/southeast asia - this has now crossed the largest continent.

http://www.bloomberg.com/apps/news?pid=10000100&sid=aL95jjBX8rDQ&refer=germany

---

Clarification of Answer by siliconsamurai-ga on 10 Jan 2006 05:13 PST

Hi, thank you for the rating and the tip.

Again, not a clarification - breaking news related to the question.

Unfortunately I feel I should let you know that there are multiple new
cases reported in Turkey this week so this is becomming a serious
concern.

http://www.bloomberg.com/apps/news?pid=10000087&sid=a7exWQFU5fqA&refer=top_world_news


A pandemic, if it occurs, will not follow the pattern of yearly flu
outbreaks with a peak just about this time of year, it would continue
through the year, especially with it being carried by migrating birds
who will be changing homes again in a few months..

And, just a reminder, when you hear of a few cases in a country with a
large rural population, there are probably (almost certainly) others
undiagnosed and therefore unreported.


The BBC is reporting
http://news.bbc.co.uk/1/hi/health/4595582.stm
that the number of bird flu cases in humans has been ?hugely? under
reported according to a Swedish study.

Instead of only about 90 cases so far in Vietnam, there may have been
thousands and perhaps as many as 750 directly related to sick birds.

The study isn?t conclusive but it does remind us that there could be
serious under reporting in rural areas where the first cases are most
likely to occur due to close contact with chickens.

The answer was well laid out and extensively researched

The reason Japanese wear masks is to prevent their cold germs from
spreading to others, not to keep out the cold virus. It is one more
politeness in their delightful but overcrowded society. Surgeons wear
masks for similar reasons, to prevent germs from their mouth and/or
nose from getting into the surgical field.

Stop worrying about bird flu and take an epidemiology course. You will
learn that the initial high mortality rate will come down as a disease
progresses for reasons not related to the actual mortality of the
disease.

You have much more to worry about from poor diet, smoking and drinking
than bird flu. If you eat well and don't smoke or drink, I've got
about 7391 things that are more likely to kill you than bird flu will
be.

Although I certainly wish markvmd was correct, unfortunately the
latest reports from real epidemiologists say that the bird flu is NOT
showing any signs of becomming less deadly as it mutates.

The strains in Turkey were closer to a human-transmittable variant and
it still has about a 50% mortality rate, not the 5-10% rate which many
of us had hoped for.

Bird flu is now rates by the WHO as by far the most dangerous threat
to human life and says money being spent on anti-terrorism efforts are
misplaced considering the much greater danger to national and
international economies from the Bird Flu.

What skews mortality results early in a disease is that, for the most
part, it is only ill and dying people that are being tested. As a
disease matures, more people are tested and more people survive. If
you recall the AIDS progression, at first it appeared to have ~50%
plus mortality at five years; five years later the mortality was ~50%
at ten years. Now (25+ years) the mortality is vastly improved, mostly
via drug therapy but also through wider sampling. The flu of 1918
followed a similar maturation process. I'm simplifying but I doubt
there is a reason to believe bird flu would be much different.

I'm highly suspicious of media statements that seem to always name a
particular brand of antiviral that just happens to be affiliated with
the US vice president, yet almost never mention the rival product.

Sorry, I meant to say "more people are tested and more people ARE
SHOWN TO survive" above.