Posted on 02/01/2004 9:02:44 PM PST by saquin
The prospect of a terrorist, self-infected with a deadly disease at a stage before it shows its symptoms, boarding an aeroplane to infect tens or hundreds of other passengers is what risk experts call a "low likelihood, high impact" threat.
Despite sounding as unlikely as the plot of a trashy novel, the threat was considered real enough on Saturday for the American government to refuse security clearances for six flights to America.
It is deemed "low likelihood" because of the difficulty terrorists would face in obtaining or manufacturing a viable biological agent, yet "high impact" because of the ease with which disease would spread in the confined space of an airliner, eventually to infect millions.
The practice of recirculating cabin air to cut fuel costs has already been blamed for spreading colds, flu and gastrointestinal infections that have struck down 200 passengers at once.
Older aircraft such as Concorde and the Boeing 737 relied solely on air ducted from the jet engines for their ventilation. It meant the on-board atmosphere was extremely dry but at least the cabin air was replaced completely every three minutes.
Modern airliners use a 50-50 blend of fresh and old air simply because it is cheaper. Air conditioning units siphon power from the jet engines; less ventilation means lower fuel consumption.
With the increased carbon dioxide levels comes a greater circulation of particles, organisms and disease.
Potentially the biggest threat in these circumstances would be a terrorist infected with smallpox.
A single sneeze would be enough to put hundreds of thousands of saliva droplets carrying the variola virus into circulation, which would be fatal to three out of 10 people not vaccinated against the disease.
Unlike anthrax, smallpox can spread from person to person. It claimed about a billion lives before being declared extinct in 1980. "Smallpox is a very dangerous weapon in the hands of terrorists and you don't need some clever way of delivering it," said Dr Lev Sandakhchiyev, director of Russia's Vektor Institute, which holds one of only two official samples of the extinct disease.
"All you need is a sick fanatic to get to a populated place. The world health system is completely unprepared for this."
A study by Dr Tara O'Toole, of Johns Hopkins University, Baltimore, gave some indication of the "high impact" potential of a theoretical attack.
A smallpox-infected terrorist who boarded a plane on April 1 would, by mid-June, have led to 15,000 cases and 2,000 deaths in America, while the disease would have spread to at least four other countries.
Another study, by the American government, predicted three million cases and one million deaths within a few months of the first infected patient.
Smallpox is on a list of biological agents "of highest concern" issued by the US Centres for Disease Control and Prevention in Atlanta, Georgia. The list includes bubonic or pneumonic plague, which can be passed person to person, tularaemia (an acute infectious disease of rodents transmitted by ticks or flies) and Lassa fever.
Experts believe smallpox, anthrax, botulism and plague are the most likely pathogens to be used.
We're talking about a quantity of air (equivalent to a portion of the cabin air contimuoussly being drawn from the cabin at a given time) that would be miniscule in comparison to the tremendous volumes of air taken into the aforementioned combustion chambers in a single second.
The system essentially would be closed and would be controlled by valves, one-way and otherwise; sensors; etc. The efficiency of the aircraft's engines would be virtually unaffected while the microbial content of cabin air at any given point in time would be minimal.
For even the most virulent of infections, multiplicity of infection -- i.e., the number of bugs that enter the body of a potential host during exposure to an etiologic agent-- is critical re: whether one becomes "exposed" to the extent that the pathogens in question can multiply at all or beyond the capacity of an individual's specific and non-specific immune respionses to successfully address.
Indeed, the small volume of air expelled during one or many sneezes and coughs by an individual infected with smallpox, ebola, etc. would be drawn immediately and ++without fanfare under negative pressure into vents above and below each seat and other areas of a fully-laden aircraft and subsequently submitted to incineration as described in the foregoing.
Granted, I'm only a fifty-year-old-plus. doctoral-level microbiologist, but at present have a few of my Gyro Gearloose-type engineering friends working up a small working prototype for the purposes of submitting a patent in the very near future.
Hopefully you can "read all about it" and benefit therefrom someday soon. Sleep well, and happy trails to us all...
Biowarfare aside, it might improve the quality of cabin air in general -- I always get a cold when I first travel by air after a period of staying put.....
"One Liberal Socialist as US President could lead to death of 300 Million people!"
Potentially the biggest threat in these circumstances would be a terrorist infected with smallpox.
By the time a persons smallpox is contagious, they will be covered with festering blisters and will be in a near bedridden state.
Comforting. What ever happened to the US smallpox immunization program that got underway after 911??
They seem to be missing on that one more often recently.
We desperately need to have cowpox in this country again.
It would possibly save the Gov't a fortune (and taxpayers) to let people obtain vaccinations at their discretion and expense now. It would also cut down on the logistical problems of attempting mass vaccinations in a panic situation.
"It would possibly save the Gov't a fortune (and taxpayers) to let people obtain vaccinations at their discretion and expense now. It would also cut down on the logistical problems of attempting mass vaccinations in a panic situation."
I agree completely. I think the government should not PREVENT us from making the decision for ourselves, which is exactly what they are doing now.
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