Biological terrorism. Germ warfare. These words can strike fear into the hearts of the population, as people wonder when the next terrorist threat will arise. The danger of bioterrorism hangs over our heads like a modern sword of Damocles.
We all remember the anthrax scares from 2003, right? Anthrax has certain advantages as a biological weapon. It’s a common agricultural disease. It can be easily obtained from Third World countries from blood scrapings off of diseases cattle. It also has a durable bacterial spore form which is convenient for dispersion via aerosols. However, it is not highly contagious; in fact, there are no known cases of person-to-person transmission. For maximum impact, the weaponized grains of anthrax culture must be inhaled, and getting the right grain size to ensure both dispersion and inhalation can be difficult. These factors severely limit its effectiveness as a biological threat.
What about other pathogens, such as choleral, yellow fever or the ebola virus? These typically present challenges as well. Sometimes, it can be difficult to isolate a sufficiently virulent strain, which is especially important when the pathogen has limited transmissibility. In addition, there are significant engineering obstacles; for example, there is the challenge of dispersing aerosolized germ powders through a tiny nozzle without any clumping or clogging.
Of course, any sort of biological agent is extremely dangerous to cultivate or deploy. This reduces the threat that they present, as only a lunatic would deliberately attempt to handle such weapons. Unfortunately, history has shown that there is no shortage of lunatics in terrorist circles.
This is where smallpox comes into the picture. “But wait!" one might say. “Hasn’t smallpox already been eradicated? The World Health Organization embarked on a massive immunization program, finally declaring in 1977 that smallpox had been wiped out." That’s only partially true, though. While smallpox is no longer a threat to the populace at large, samples of the smallpox vaccine were still kept in government labs within the USA and Russia.
In 1992, a Soviet defector to the United Kingdom revealed that he had overseen an extensive (and illegal) program for weaponizing smallpox. Another Soviet scientist confirmed this claim, and expressed his belief that unemployed or underpaid scientists may have clandestinely sold some of the smallpox samples to rogue terrorist nations.
Western intelligence agencies have reason to believe that three countries - North Korea, Iraq and Russia - have the capacity to deploy smallpox as a weapon of mass destruction. Other countries are likewise suspected of having inadvertently or deliberately retained specimens of the virus; these nations include China, Cuba, India, Iran, Israel, Pakistan and Yugoslavia.
Smallpox is not highly contagious; however, it can be transmitted through prolonged contact, and the symptoms can be severe. Apart from the usual fever, it can also leave someone covered with hideous pustules (rather like an outbreak of chicken pox, but many times worse) and can produce permanent scarring.
What measures can be taken to protect one’s self against smallpox? Vaccinia, the currently licensed smallpox vaccine, has proven its effectiveness; however, it is only available in limited quantities. More importantly, vaccinia can produce some dangerous side-effects, including severe rashes and some potentially life-threatening conditions (e.g. eczema vaccinatum, post-vaccinal encephalitis, and possibly myopericarditis). Also, there are some doubts about how effective this vaccine will be against certain smallpox strains.
For these reasons, long-term research is underway to develop a safer vaccine that will provide an effective immune response without the unfortunate side-effects of vaccinia. This vaccine (modified vaccinia Ankara, or MVA) has been shown to be nearly as effective as vaccinia in protecting monkeys from monkeypox (which greatly resembles the smallpox virus) while mitigating the unpleasant symptoms. Further testing will be required to determine how effective MVA would be against the smallpox virus itself. Until then, existing doses of vaccinia can be diluted by a 1:10 ratio, if necessary, and still generate an adequate immune response.
The bottom line: Smallpox may have been eradicated from the wild, but there’s reason to believe that some strains may be in the hands of some hostile sources. The existing virus also has some unpleasant side-effects, and there is some doubt about the extent of its effectiveness against certain strains. Fortunately, smallpox itself is only moderately contagious, requiring prolonged exposure. In addition, the traditional vaccine has proven its effectiveness against the primary smallpox strain, and some encouraging research is underway toward developing a much-improved vaccine that avoids the current unpleasant side-effects.
About the author:
V. B. Velasco Jr. is a senior engineer at a small biotechnology firm that provides ELISPOT plate readers, cryopreserved PBMC, CEF peptide pools, and contracted research services.
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