Plague can be compared with tularemia, which comes in two forms. Today, the more well known form is considered a debilitating, incapacitating disease. The other form is the one originally developed as a weapon. It causes substantial mortality. Thus, the approaches to these two agents are quite different, the results they produce are quite different, and the way we must deal with them will be different.
There are also transmissible and nontransmissible agents. Smallpox, which is highly transmissible, can be compared with anthrax, which is not transmissible from person to person. The significance of this is great. One individual with smallpox will infect anywhere between 10 and 50 others, creating a mushrooming problem.
There are persistent and non-persistent agents. The classic Biological Weapon (BW) organism, anthrax, is persistent and hardy. Given the right conditions, it can survive in the environment for well over 100 years. Anthrax can be compared with Venezuelan equine encephalomyelitis, a virus that is nonpersistent in the environment.
Of course, there are overarching classifications of living BW organisms, divided into bacteria and viruses. Brucella can be compared with Marburg virus, for instance, and there are many other examples. The big difference is whether or not vaccines and therapeutic treatment agents exist. On the whole, there are very few drugs available to treat viral diseases. This is a large hole in our defensive armamentarium.
There are living and nonliving agents. Plague, for example, is a living agent. Botulinum toxin and ricin, on the other hand, are clearly nonliving chemicals.
Finally, there are the even more general categories of human diseases versus animal diseases versus plant diseases. There are organisms that can attack any part of the living world that we depend upon, ranging from salmonella infections in humans, to foot-and-mouth disease in cows, and Bunt of Wheat in food crops.
So, biological weapons are a family of weapons. This must be emphasized. People talk about straightforward “ballistic” weapons, but they never confuse the use of a tank with the use of a handgun. Tanks and handguns are designed to do different jobs in the hands of different kinds of people. Similarly, it is important that the same distinction be drawn in talking about biological weapons, a family of weapons that can be used in circumstances that range from individual assassinations to mass killing of civilian populations.
The modern era has seen several biological weapons programs, including two, in particular, that were very large. The United States had a very large offensive biological weapons program, which it unilaterally abandoned in 1969, in the lead-up to the 1972 Biological and Toxic Weapons Convention. The Soviet Union had a truly enormous offensive biological weapons program.61 Now there are about a dozen countries that have been assessed as having, or are suspected of having, offensive biological weapons programs; without discussing details, suffice it to say that these programs and the people with the skills to run them do exist.