AlaskaDenise
In Memoriam
http://www.thejakartapost.com/detailfeatures.asp?fileid=20060913.T02&irec=1
The term "pandemic" describes the spread of a specific agent of disease across continents. It is an epidemic that goes global. In the case of influenza, history tells us pandemics occur roughly once every 30 or 40 years.
Think of coconuts again. Coconut trees in the Thousand Islands will have a very high success rate for landing coconuts on tropical sandy beaches: It's hard to avoid islands out there.
The normal human influenza virus, causing millions of infections around the world every year, enjoys this kind of target-rich environment.
Now picture a lone coconut tree on a sandy atoll many hundreds of miles from the nearest beach: It may take many seasons of dropping coconuts before one eventually finds its way.
A pandemic strain of influenza faces odds like that -- 30 to 40 years of constantly throwing out variants before one particular variant finally finds its way to pandemic. It not only must have the genetic makeup suited to causing pandemic, but it must also find its way into sustained transmission among humans.
Bird flu pandemic
H5N1 will not cause a pandemic in humans. It may, or may not, give rise to the variant that lands on the viral sandy beach called pandemic, but as it is currently constructed it is incapable. It has failed uncounted millions of attempts to do so -- its coconuts have invariably sunken out of sight.
The fear is that H5N1 will change itself sufficiently, probably by a genetic shift event combining its seemingly high capacity for causing disease with the capacity for efficient transmission from a normal human influenza virus.
Such an event could happen in any animal capable of hosting both normal human influenza and strains adapted to animals like chickens or pigs.
This is the reason experts express such concern about people and domesticated animals living in close proximity -- it amplifies the odds of a successful genetic shift, in essence, moving the viral coconut tree closer to friendly beaches.
The fear of such a virus causing the mortality rates now observed with H5N1 is irrational. First, as already explained, it almost certainly is much less lethal than it appears with the very limited sampling done so far.
Second, Nature does not make it easy for highly dangerous viruses to go pandemic. There are formidable barriers to the spread of rapidly lethal viruses. The balancing act of such viruses is conspicuously lousy.
We know this for simple reason that such viruses have, as far as we know, never caused a pandemic in human history despite very efficient transmission and an almost continuous presence (Ebola virus, for example).
If H5N1 gives rise to a pandemic-capable variant, and it finds its way into sustainable human-to-human transmission, a likely outcome will be a "normal" pandemic. "Normal pandemics" are like most of those that have occurred before, and this should not be confused with an "extraordinary pandemic", like the 1919 Spanish Flu pandemic (prior paragraph said therehad never been a pandemic) (which killed far more efficiently than any other known pandemic, an estimated 2-4 percent of those infected).
With intervals of 30 to 40 years, and modern biology capable of understanding viruses reaching back only about 80 years (most scientists accept a reach of 300 years understanding on pandemic cycles), our sample for understanding what is normal and what is extraordinary is limited.
Nonethelss, based on what we know, the next pandemic is likely to occur sooner rather than later, and it is most likely to kill fewer than 0.1 percent of those infected (as in all other pandemics except the 1919 event, according to Taubenberger and Morens in Emerging Infectious Diseases, Vol 12, No. 1 January 2006).
In 2002 the eminent influenza virologist, M.R. Hilleman, wrote (in Realities and enigmas of human viral influenza: pathogenesis, epidemiology and control in the peer-reviewed medical journal Vaccine volume 20, pages 3068-3087), "Within the small universe of experience, the 1918 (influenza) virus was unique in its virulence that was of chance occurrence. There is no evidence to support a belief that its unusual composition and high level of toxicity will be duplicated in future pandemics."
What he is saying is that the coconut that landed on pandemic beach in 1918 was a weird one, and that while we can expect further landings, we should not expect them to be as weird -- and we certainly should not expect them to be lethal far beyond a degree ever encountered before. This statement best represents the credible and responsible voice of well-informed reason.
The face of pandemic flu
When the pandemic-capable strain finally emerges and finds its way to sustainable human-to-human transmission, its identity will be unmistakable.
It will be a variant not seen before. We will notice clusters of cases occurring at increasingly short intervals and involving increasingly greater numbers of people having less and less direct contact.
The true case fatality rate will not be known until after the first wave of infections passes. The virus may change further (as it did in 1919) and its true danger and impact will not be fully understood until well after the global event has passed.
The difference between what appears to be happening and what is actually happening will be shaped by our expectations before the event. This is critically important to all of us.
The face of panic
I often ask people what they think pandemic bird flu would look like. Most describe biological "Armageddon".
They have created their own chimera virus clipped from the 70 percent mortality rates for H5N1 in Indonesia, the 40 million dead from the 1919 Spanish Flu pandemic, and the hopelessly over-crowded cities linked by superhighways and jets that did not exist in 1919.
It is a frightening scenario widely accepted by the public as virtually imminent. For all of the reasons explained here, it is unlikely to such an extreme as to be considered irrational, like anticipating a major meteor strike as imminent simply because it is possible.
The odd silence on the grip this scenario finds in the public consciousness from authoritative health agencies does not help: Perhaps they are not accustomed to addressing phantoms.
The frenzied reporting by the media, and frightening documentaries on highly regarded television channels all throw more gasoline on the fires of this fear.
Bird flu represents a hair-triggered gun held to the head of humanity -- by its own hand. When pandemic breaks and people start dying (they will, and even 0.1 percent mortality will be noticeable), the pressure on the trigger rises.
Panic will threaten the sustainability of workplaces and thus threaten social and economic order. The risk of workplace failures represents a far greater danger to humanity than any virus.
(J Kevin Baird)
The term "pandemic" describes the spread of a specific agent of disease across continents. It is an epidemic that goes global. In the case of influenza, history tells us pandemics occur roughly once every 30 or 40 years.
Think of coconuts again. Coconut trees in the Thousand Islands will have a very high success rate for landing coconuts on tropical sandy beaches: It's hard to avoid islands out there.
The normal human influenza virus, causing millions of infections around the world every year, enjoys this kind of target-rich environment.
Now picture a lone coconut tree on a sandy atoll many hundreds of miles from the nearest beach: It may take many seasons of dropping coconuts before one eventually finds its way.
A pandemic strain of influenza faces odds like that -- 30 to 40 years of constantly throwing out variants before one particular variant finally finds its way to pandemic. It not only must have the genetic makeup suited to causing pandemic, but it must also find its way into sustained transmission among humans.
Bird flu pandemic
H5N1 will not cause a pandemic in humans. It may, or may not, give rise to the variant that lands on the viral sandy beach called pandemic, but as it is currently constructed it is incapable. It has failed uncounted millions of attempts to do so -- its coconuts have invariably sunken out of sight.
The fear is that H5N1 will change itself sufficiently, probably by a genetic shift event combining its seemingly high capacity for causing disease with the capacity for efficient transmission from a normal human influenza virus.
Such an event could happen in any animal capable of hosting both normal human influenza and strains adapted to animals like chickens or pigs.
This is the reason experts express such concern about people and domesticated animals living in close proximity -- it amplifies the odds of a successful genetic shift, in essence, moving the viral coconut tree closer to friendly beaches.
The fear of such a virus causing the mortality rates now observed with H5N1 is irrational. First, as already explained, it almost certainly is much less lethal than it appears with the very limited sampling done so far.
Second, Nature does not make it easy for highly dangerous viruses to go pandemic. There are formidable barriers to the spread of rapidly lethal viruses. The balancing act of such viruses is conspicuously lousy.
We know this for simple reason that such viruses have, as far as we know, never caused a pandemic in human history despite very efficient transmission and an almost continuous presence (Ebola virus, for example).
If H5N1 gives rise to a pandemic-capable variant, and it finds its way into sustainable human-to-human transmission, a likely outcome will be a "normal" pandemic. "Normal pandemics" are like most of those that have occurred before, and this should not be confused with an "extraordinary pandemic", like the 1919 Spanish Flu pandemic (prior paragraph said therehad never been a pandemic) (which killed far more efficiently than any other known pandemic, an estimated 2-4 percent of those infected).
With intervals of 30 to 40 years, and modern biology capable of understanding viruses reaching back only about 80 years (most scientists accept a reach of 300 years understanding on pandemic cycles), our sample for understanding what is normal and what is extraordinary is limited.
Nonethelss, based on what we know, the next pandemic is likely to occur sooner rather than later, and it is most likely to kill fewer than 0.1 percent of those infected (as in all other pandemics except the 1919 event, according to Taubenberger and Morens in Emerging Infectious Diseases, Vol 12, No. 1 January 2006).
In 2002 the eminent influenza virologist, M.R. Hilleman, wrote (in Realities and enigmas of human viral influenza: pathogenesis, epidemiology and control in the peer-reviewed medical journal Vaccine volume 20, pages 3068-3087), "Within the small universe of experience, the 1918 (influenza) virus was unique in its virulence that was of chance occurrence. There is no evidence to support a belief that its unusual composition and high level of toxicity will be duplicated in future pandemics."
What he is saying is that the coconut that landed on pandemic beach in 1918 was a weird one, and that while we can expect further landings, we should not expect them to be as weird -- and we certainly should not expect them to be lethal far beyond a degree ever encountered before. This statement best represents the credible and responsible voice of well-informed reason.
The face of pandemic flu
When the pandemic-capable strain finally emerges and finds its way to sustainable human-to-human transmission, its identity will be unmistakable.
It will be a variant not seen before. We will notice clusters of cases occurring at increasingly short intervals and involving increasingly greater numbers of people having less and less direct contact.
The true case fatality rate will not be known until after the first wave of infections passes. The virus may change further (as it did in 1919) and its true danger and impact will not be fully understood until well after the global event has passed.
The difference between what appears to be happening and what is actually happening will be shaped by our expectations before the event. This is critically important to all of us.
The face of panic
I often ask people what they think pandemic bird flu would look like. Most describe biological "Armageddon".
They have created their own chimera virus clipped from the 70 percent mortality rates for H5N1 in Indonesia, the 40 million dead from the 1919 Spanish Flu pandemic, and the hopelessly over-crowded cities linked by superhighways and jets that did not exist in 1919.
It is a frightening scenario widely accepted by the public as virtually imminent. For all of the reasons explained here, it is unlikely to such an extreme as to be considered irrational, like anticipating a major meteor strike as imminent simply because it is possible.
The odd silence on the grip this scenario finds in the public consciousness from authoritative health agencies does not help: Perhaps they are not accustomed to addressing phantoms.
The frenzied reporting by the media, and frightening documentaries on highly regarded television channels all throw more gasoline on the fires of this fear.
Bird flu represents a hair-triggered gun held to the head of humanity -- by its own hand. When pandemic breaks and people start dying (they will, and even 0.1 percent mortality will be noticeable), the pressure on the trigger rises.
Panic will threaten the sustainability of workplaces and thus threaten social and economic order. The risk of workplace failures represents a far greater danger to humanity than any virus.
(J Kevin Baird)