Whether it’s an outbreak of Ebola virus, anthrax, or Zika virus, Mother Nature likes to keep us humble. Infectious diseases have shaped history and brought down empires. When Europeans came to the New World, infections they carried with them, like smallpox and measles, killed more Native Americans than bullets. By some estimates 95 percent of the indigenous population was wiped out by these illnesses.1
We witnessed havoc and fear in the United States in 2014–16 when an Ebola outbreak struck an ocean away in West Africa. Just imagine the potential panic from a bioterrorist attack with Ebola inside the United States. Ebola enjoys membership in an exclusive “club” of infectious pathogens with properties that make a “good” bioweapon, but despite its high fatality rate and fear it engenders, Ebola is not the top dog . . . not by a long shot.
Countries continually seek new ways to gain military advantage. Humans have dreamed up chemical and nuclear agents to tip the balance in warfare. Mother Nature gave us the tools for biological (germ) warfare to unleash deadly contagion against our enemies through living organisms or toxins they produce. A germ attack can be executed in multiple ways, depending on an enemy’s objectives and sophistication.
Something as simple as human feces or a dead animal carcass can become a weapon if dropped into an enemy’s well to contaminate the water supply. Move up one level of sophistication by burying a sharp stake smeared with feces, and you’ve created a punji stick, a simple weapon used against our forces in Vietnam to pierce a combat boot and cause a horrible, putrefying infection.
Germ warfare jumped to a new level of sophistication in the early twentieth century when the superpowers harnessed microbiology to create new tools of death. The U.S. government officials feared that the Japanese and the Germans had gotten the jump on them and didn’t want to fall behind. In 1943 universities and pharmaceutical companies joined the government in a top-secret program to develop germ weapons, which was headquartered at Camp Detrick, Maryland (now Fort Detrick). Other countries joined the germ “arms race,” including the United Kingdom, Canada, Japan, and the former Soviet Union. Iraq, Syria, Libya, North Korea, and Iran, all suspected of supporting terrorism, probably also launched their own programs, not only in biological weapons, but also in chemical weapons. The U.S. program conducted elaborate tests to assess the country’s vulnerability to a bioweapon attack. Simulant organisms, which were similar to bacterial pathogens but not deadly, were released off the coast of San Francisco, with collection devices arrayed all around the Bay Area that showed that the organisms went far and wide. Another experiment placed a simulant for anthrax in light bulbs that were then shattered on the tracks of the New York City subway. The moving subway cars acted like pistons, pumping the organisms throughout the subway system.
Although they ran different weapons programs on opposite sides of the globe, the Soviets and the Americans selected surprisingly similar pathogens to weaponize and cause diseases such as anthrax, botulism, tularemia, Q fever, and Venezuelan equine encephalitis (VEE). Clearly, those agents were selected for their unique properties, but it probably helped that Soviet spies during the Cold War had infiltrated Fort Detrick.
The Soviets also seemed enamored of deadly or contagious agents causing diseases like smallpox, plague, and influenza—yes, the flu! Mother Nature then would do the dirty work of spreading the disease like wildfire, once the Soviets lit the kindling.2
The Americans, on the other hand, favored incapacitating weapons. A sick person ties up more people caring for him or her than a dead one. The Americans also considered the advantage of destroying crops and developed wheat stem rust and rye stem rust, because if an army “runs on its stomach,” an adversary can’t go far if you wipe out its rations.3 A strike against our cattle or swine populations or wheat fields could destroy large segments of our economy and roil the stock market.
Not every microbe makes a “good” biological weapon for war, but if chosen and released correctly, the right weapon could wipe out enemy forces and possibly determine the outcome on the battlefield. The “best” weapons share some key properties: They survive well and infect efficiently in the air. They grow easily enough to generate large quantities to spray over a battlefield. They are highly infectious, sickening most of their exposed victims, and they shouldn’t come back to infect one’s own troops, so it helps to develop vaccines against them.
Biological weapons are fickle, though, so timing is everything. The weather must cooperate. You can’t unleash an attack in a thunderstorm. A gentle, steady wind is ideal for wafting an airborne weapon toward the enemy—but not too fast, or the aerosol dissipates. Too slow or in the wrong direction, and you miss the target, or it comes back to bite you. The sun degrades most organisms, so better to release them at nighttime for maximizing casualties, when the stealthy night air creates an inversion and hugs the weapon close to the ground and its intended victims.
Bioterrorists may have different requirements, depending on whom they target and whether they seek to kill people, sicken them, scare them, or just make a political statement. They may need smaller amounts than used in warfare to assassinate a political figure, contaminate a salad bar, or kill a neighbor.
Among the thousands of possible microbes, the cast of frightening diseases with the properties that make a “good” bioweapon shrinks considerably. The Centers for Disease Control and Prevention (CDC) dubs the six highest threats as “Category A” agents. I call them the “Chessmen of Doom”:
Each pathogen has unique skills and attack strategies to outmaneuver humans and rain death and destruction on individuals or societies.