Concerns about use of Ebola as a bioweapon exaggerated: Experts

If an infected terrorist carrying the virus would arrive in an advanced country, the toll of the attack would not be high. Even if he managed to infect a few people, the health systems in advanced countries would quickly isolate the infected individuals to prevent mass contagion – and perhaps even manage to cure most of those infected by using experimental medications such asZMapp.

The effect of an Ebola virus terrorist attack would thus be more psychological, and may also lead to some economic disruption, but it would not result in the massive waves of infections that have paralyzed Liberia and inflicted heavy damage on Guinea and Sierra Leone.

“Someone gets sick on an airplane, conceivably everyone on that airplane has to be quarantined,” said Dr. Robert Kadlec, who was special assistant on biodefense policy to President George W. Bush.

The U.S. government considers Ebola and other hemorrhagic fever viruses as among the most serious potential bioterrorism agents, along with those that cause smallpox, anthrax, botulism, plague, and tularemia.

“It’s not very contagious compared to things like plague, but it does have high lethality and could cause fear and terror,” Dr. Amesh Adalja, a senior associate at the Center for Health Security, which is affiliated with the University of Pittsburgh Medical Center, told the Times.

The idea of using the Ebola virus as a weapon is not new. A congressional investigation reported that before they killed thirteen people with nerve gas in the Tokyo subways in 1995, members of the Japanese cult Aum Shinrikyo traveled to Zaire — ostensibly a medical aid mission, but the real purpose was to collect Ebola samples to be used in a terror attack back home in Japan. The cult failed, however, in its quest.

The Soviet Union tried to develop an Ebola-based bioweapon, but switched its focus from Ebola to the closely related Marburg virus, according to Raymond A. Zilinskas, director of the chemical and biological weapons nonproliferation program at the Monterey Institute of International Studies.

Dr. Zilinskas, who is a co-author of The Soviet Biological Weapons Program: A History (Harvard University Press, 2012), told the Times that the Soviets might have encountered difficulties in mass producing Ebola. He said they did manage to mass produce the Marburg virus in a form that could be stable if dispersed through the air, but he doubted that terrorists could do the same.

“You are talking about highly capable people working on it for years,” he said. “That’s not terrorists.”

A terrorist intent to infect himself could easily do so by rubbing against a corpse or by using bodily fluids from an infected person. Ebola hemorrhagic fever has an incubation period estimated at two to three weeks, and many people would not have symptoms for a week or more after being exposed.

“So they could get on an airplane and get through customs and not be symptomatic and be in downtown Minneapolis before we know it,” Dr. Hall said.

Dr. Adalja said, however, that such a situation was not plausible. He noted that infected people are not contagious until they have symptoms, at which time they might not have the strength to go to a public place to infect others. Also, contact with bodily fluids is required, so “You have to literally vomit on them,” he said.

Experts also note that the inability of Ebola to be transmitted from person to person by air would impose an additional limit on its effectiveness as a weapon of mass destruction. Researchers also say that it is not clear how stable the virus would be when exposed to ultraviolet light.

One study by Army researchers showed that when forced to inhale Ebola virus, monkeys could be infected. Another study published by Canadian scientists two years ago found that pigs could transmit the virus through the air to monkeys in nearby cages.

— Read more in E. Johnon et al., “Lethal experimental infections of rhesus monkeys by aerosolized Ebola virus,” International Journal of Experimental Pathology 76 (1995): 227-36; and Hana M. Weingartl et al., “Transmission of Ebola virus from pigs to non-human primates,” Scientific Reports 2, Article number: 811 (15 November 2012) (doi:10.1038/srep00811)