Dropping the H-Bomb

How dangerous is a “herpes bomb”?

Amy Bishop. Click image to expand.
Amy Bishop

News reports suggest that Amy Bishop, the biology professor who shot six of her colleagues at the University of Alabama-Huntsville on Feb. 12, may also have planted a “herpes bomb” in the building where she worked. Bishop conducted research on the virus as a post-doctoral fellow. Would a herpes bomb be dangerous?

Probably not. The herpes virus is fragile, minimally transmissible, and rarely deadly, which is why no government or terrorist group has ever made a herpes-based device, as far as we know. Herpes virions can’t survive the heat of an explosion, and they don’t spread well through the air. (Varicella, or chicken pox, is the only common member of the herpes family that can go airborne, but most adults are immune to the disease, so it wouldn’t make a good weapon.) In order for a herpes bomb to make anyone sick, the virus particles would first have to survive the explosion and then be thrown into direct contact with a victim’s mucosal surface, like the insides of his mouth or genitals, or into his eyes. They could also land on a wound or open sore, and thus enter his bloodstream directly. Plus, if Bishop’s bomb hasn’t gone off yet, it probably expired several days ago. Herpes can’t last more than a couple of days outside the body at room temperature, even in a pH-balanced saline solution.

A successful herpes attack isn’t likely to cause much suffering, anyway. Ninety percent of adults over 50 have already been exposed to the oral form of herpes, and 22 percent have been exposed to the genital form. Many people experience no symptoms at all from these viruses, and most of the others only develop a few sores as a result of infection. The worst-case scenario is brain swelling, but that typically occurs in patients whose immune systems are compromised, like pregnant women, people with HIV/AIDS, and those undergoing cancer treatment. There are more deadly forms of herpes, like Herpes B, which is carried by macaques and kills more than 50 percent of the people who contract it. A successful attack with one of these strains could indeed be deadly, but there is no indication that Bishop had access to any of them.

It’s not easy to build a biological weapon, even if you do have a big enough supply of virus particles. Soviet and American experts spent years developing a form of Venezuelan Equine Encephalitis virus that could be deployed in a military context. They first had to derive a particularly tough strain. Then they formulated a chemical shell to protect it from the hot and dry explosion required to disperse the virus, and also to give it some added bulk so the victim’s breath wouldn’t blow it right back out after it landed inside the mouth, throat, or lungs. (The ideal diameter is between one and three microns. Herpes, like many viruses, is around one-tenth that size.) It is unlikely that an assistant professor with no professional experience in biological weapons development would have the expertise to accomplish these steps.

The anthrax letters of 2001—which seem to have been the work of a sophisticated scientist—were among a very small number of terror attacks in which aerosolized pathogens were used to infect the intended victims. Those with less expertise are better off using food- or waterborne pathogens. The Rajneeshees, a religious cult in Oregon, managed to infect 751 people in 1984 with Salmonella by contaminating restaurant salad bars. In any event, Bishop seems to have had enough experience to know that a bomb would be an impractical method of infecting her colleagues. Instead, she might have tried contaminating their laboratory equipment or pouring a saline solution containing the virus into their water bottles.

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Explainer thanks Bryan R. Cullen of Duke University, Nishal Mohan of the Federation of American Scientists, Patricia Spear of Northwestern University, and Raymond Zilinskas of the James Martin Center for Nonproliferation Studies.

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