There has been much talk of the possibility of terrorists using chemical or biological toxins in any sequel to the horrific events of September 11th in the US. The decision by the World Health Organisation to advise governments formally to take precautions against the possibility of bio-terror has added a certain chilling gravitas to the speculation.
Biological weapons, by their very nature, will not produce instant devastation in the way that a bomb or aircraft attack can. While in an attack, casualties present themselves within minutes or hours, it is not until days or weeks after a chemical or biological attack that we can be sure of its occurrence. The time that elapses before symptoms are observed is dependent upon the actual agent used.
It is estimated that a least 70 different types of bacteria, viruses and fungi can be formulated into weapons of mass destruction. These include anthrax, Q fever, typhus, smallpox, brucellosis, botulism toxin, dengue fever, Lassa fever and the Ebola virus.
The problem from a treatment perspective is that scientists have created antibiotic resistant strains of some of these bacteria. Viruses and toxins can also be genetically altered to heighten their infectiousness, thus rendering vaccines less effective.
Clearly, then, early detection of biological weapon use will be crucial in minimising the number of casualties. Emergency response teams will rely on a Biological Integrated Detection System which can determine the presence of anthrax, plague, botulism toxin and other agents within 30 minutes of being set up.
Vaccination is a key element in protecting people from the effects of biological warfare. Smallpox vaccine can be administered either before or after infection has occurred.
On the other hand, the anthrax vaccine used in the US has to be administered six times before it becomes effective - a process that takes over 18 months to complete. However, vaccines do provide very good protection against specific biological weapons and are likely to be the principal method of minimising casualties should biological warfare ever occur.
The US spent $400 million dollars in 2000 to research new vaccines and to increase its stockpile of smallpox shots. In 1999, it had seven million vaccines available nationwide - barely enough to cover the city of New York.
Ken Alibek, a former deputy chief of the Soviet biological weapons programme, suggests we need to focus on other ways of boosting the non-specific immune system which he believes may offer at least temporary protection. Writing in his book, Biohazard, he says of non-specific immune system boosting:
"If administered in the crucial first hours after an attack - when authorities are still trying to identify which agent was used and organise a medical response - such a booster could help contain the crisis. Everything I know about biological weapons tells me this is more promising than attempts to rig office buildings and public monuments with detection devices or to stockpile vaccines". There is a theoretical possibility of administering non-specific immune system boosting agents - such as interferon - in the crucial first hours of an attack. To the best of my knowledge, however, such an intervention has not been researched in any practical way.
What might happen if smallpox (Variola Major) was deliberately released as part of a biological attack? We have to go back to 1959, when 46 Muscovites were infected with smallpox by a visitor from India, to get some idea of how to react. The Russian authorities at the time prevented a major epidemic through vigorous quarantine measures as well as widespread vaccination.
So it is not all doom and gloom in the event of a terrorist-induced smallpox attack. With an incubation period of seven 10 days, there would be a clear window of opportunity for health authorities to commence a programme of mass vaccination.
Smallpox immunisation is thought to become effective within a few days. It must also be administered before the first symptoms appear.
Once symptoms develop, however, there is no specific drug treatment for the condition. It has a high morbidity rate of 60 to 90 per cent; some victims are permanently blinded and many must live with permanent scarring.
From a purely parochial perspective, the Republic is unlikely to appeal as a target for bio-terrorists. Apart from considerations of neutrality, even Dublin is a small target in international terms. Nor does it have an underground transport system or underground shopping malls - both ideal locations of the release of biological weapons.
On a global level, the entire concept of chemical and biological warfare is highly repugnant and has no place in modern scientific or medical research.
E-mail Dr Muiris Houston, Medical Correspondent, at mhouston@irish-times.ie, or leave a message on 01-6707711 ext 8511. He regrets he cannot reply to individual problems