Are we ready for biological warfare?

The recent outbreak of the Nipah virus has brought the fear of emerging new infections to the fore. Healthcare workers are worried about the advent of new epidemics. It is likely that the spread of an epidemic would be rapid and consequently difficult to contain. But while the threat of new infections is real enough, the threat of a biologically manufactured organism causing a biowarfare-like scenario is more likely. Advances in molecular biology make it easy to manufacture new organisms or manipulate the genes of existing agents.

Nuclear weapons may not be a serious terrorist threat. The technological considerations are many and it would be difficult for a terrorist group to cause a catastrophic nuclear explosion, unless they are helped by a rogue nation. Biological proliferation is an entirely different matter. Unlike nuclear weapons, subterfuge is not necessary in the pursuit of bioterrorist weapons. Legitimate academic research can function as cover for their development.

Experiments have shown that the ability to produce dangerous pathogens is widespread. A 2001 research paper described how the mouse pox virus could be manipulated to produce a far deadlier organism. Routine methods were used and the experiments were performed in standard laboratories. Admittedly, the organism involved was a mouse. Nevertheless, it is chilling to imagine humans being at the receiving end of such genetically modified organisms.

Organisms that are presently at the forefront in biowarfare are anthrax, botulinum and smallpox. Anthrax has been used as a bioterrorist weapon. In 2001, anthrax spores were mailed to the offices of newspapers and to two American senators. The sender was never found.

Botulinum is a toxin 50–100 times more toxic than cyanide when taken orally. The bacteria are easy to grow and the toxin is relatively easy to produce in large quantities. Fortunately, weaponising the toxin is difficult and this makes it unlikely that botulinum would be used as a bioterror weapon.

Smallpox is a likely contender for a bioterrorist attack. The organism has been used as a weapon in the past. It is believed that US Army soldiers distributed smallpox infested blankets to Mandan Indians in 1837. That smallpox has been eradicated from the globe (the last case was reported in Somalia in 1977) makes a resurgence of the virus all the more alarming. This is because vaccination has been stopped and a large portion of the global population have no immunity against the disease.

Theoretically, smallpox exists only in two locations which are supposedly well-monitored. However, doubts have been cast upon the safeguards. Reports mention that the erstwhile Soviet Union had weaponised smallpox. With the breakup of the Soviet Union, the possibility of small quantities of the virus having fallen into the wrong hands remains a chilling possibility.

Though a vaccine is available against smallpox, it is debatable if stocks are available for the entire human population. Again, the use of the vaccine is controversial. Vaccines can cause one to two deaths per million vaccinations. Immunocompromised patients, including those with HIV and uncontrolled diabetes, would be prone to the side-effects. A vaccination programme against smallpox is therefore fraught with problems.

An ideal biological warfare agent should be virulent, with high host specificity; it should be controllable, capable of resisting adverse climatic conditions and easy to camouflage. However, for a bioterrorist group, there is no requirement to control the organism after release. Most apocalyptic terrorists would not be bothered if they too died, along with their victims.

It should be easy for motivated terrorist groups to achieve the above objectives. Hardiness and resistance to drugs are inherent characteristics of many organisms, especially the smallpox virus and anthrax spores. Modifying the genes of an organism to enhance the virulence, pathogenicity, difficulty in detection and infectiousness is possible. Organisms can be genetically modified to evade body defences. This leads to a nightmarish scenario where there are a large number of infected people and a corresponding high mortality rate.

In recent times, new diseases have been emerging in the human population at a frequency of roughly one a year. Dramatic outbreaks of previously localised diseases like the Hanta virus have been occurring with depressing regularity. International borders no longer contain disease. The 2003 SARS epidemic showed how an emerging disease can spread rapidly, aided by international air travel.

Bioterrorist attacks have occurred in the recent past. Mass casualty terrorism was attempted by the Aum Shinrikyo when they sprayed Anthrax bacillus in Tokyo subways. The attempt failed because the group had used a non-lethal vaccine strain of the Anthrax bacillus which was not properly aerosolised. The attack was a wake-up call for humanity. With advances in Molecular Biology, would it be possible for terrorist groups to evolve organisms which can cause extensive destruction of human lives? The answer probably is, ‘Yes’. Much more than in the nuclear weapons case, the world has to come to terms with biological warfare possibilities.

(The writer is a pathologist and molecular biologist)