WASHINGTON — As the international community continues to grapple with Ebola, some in the Defense Department are concerned that the deadly virus could become airborne.
Ebola has killed nearly 5,000 people in West Africa during the latest outbreak, and officials project that thousands more in the region could die. There is no known cure or vaccine.
The good news, from a public health perspective, is that Ebola is believed to be spread only through direct contact with the bodily fluids of an infected person. That scientific understanding — along with the fact that America has an advanced health care system capable of isolating and safely treating Ebola victims — leads most experts and administration officials to believe that an outbreak is highly unlikely in the United States.
However, one Pentagon office known for thinking about and planning for worst-case scenarios isn't assuming the virus can't or won't become airborne.
On Oct. 24, the Defense Threat Reduction Agency put out a formal request to industry and other government agencies for assistance in the fight against Ebola, including a call for further study of how the disease could be spread.
"While current science indicates the disease can only be transmitted by contact with contaminated body fluids, it remains unclear if other transmission modes are feasible," the document states.
The document notes that in experimental animal models, "filoviruses are able to infect via the respiratory route and are lethal at very low doses."
In other words, DTRA wants to figure out if Ebola could go airborne. If that occurred, the disease could potentially could be transmitted by an infected person sneezing or coughing, much like the flu.
A 'frightening thing'
Although Ebola isn't in the air now, that could change, according to experts.
Mutations occur and "viruses do change mode of transmission," said David Sanders, an associate professor of biology at Purdue University who works with the Ebola virus. "The longer this epidemic persists, the greater the chances that will happen."
And the more people fall ill with the disease, he said, the greater chance of a mutation that could allow the disease to quickly spread globally.
"I know [the chance of such a mutation is] nonzero, and if you have a million cases of Ebola, the chance is 100 times greater than if there are 10,000 cases," he said.
Steven Block, a professor of biological sciences at Stanford University, said today's Ebola has a different genome sequence and doesn't cause all of the same symptoms that the disease did in the 1970s, when it first emerged.
"We know that Ebola changes and we've seen Ebola change," he said.
If it did go airborne, it would be catastrophic.
"That would be a very frightening thing and that would threaten the whole world," Block said. "We would not be in this situation we have right now where Ebola is substantially contained to within Africa."
For people over the age older than of 40, Ebola's mortality rate is more than 90 percent; for younger people, the mortality rate is about 50 percent, according to Block.
Still, he emphasized that people shouldn't panic because the virus would probably have to undergo "a number of mutations" before the mode of transmission changed.
"Is it possible that Ebola could mutate to go airborne? Yes. Is it likely? Most virologists would tell you [it's] extremely unlikely," he said.
Ebola as a weapon?
DTRA's request for research proposals suggests that some in the organization are worried that Ebola could be aerosolized — a key step in turning the disease into a biological weapon.
"There is minimal information on how well filoviruses survive within aerosolized particles," but "preliminary studies indicate that Ebola is aerostable in an enclosed, controlled system in the dark," the document states.
Block said it would take a great deal of expertise to weaponize Ebola, as well as major laboratory resources, so it's not something a terrorist group could do easily.
"It is possible, in principle, to get Ebola into an aerosolized particle, to get that into the lung, and to infect somebody," he said. "But it's not what you would call a two-men-in-a-tent kind of thing ... We're talking about probably millions of dollars of funds and investment and probably people with doctoral-level experience ... doing this kind of stuff."
The engineering would have to be very precise.
"The weaponization consists of how do you disperse it in an aerosol," Block explained. "Aerosol has to be just the right size particle. If the particle is too big, it falls to the ground and it doesn't work. If it's too small, it evaporates quickly and the virus is dead."
And a person without a deep biological sciences background in the biological sciences could easily harm themselves if they tried to handle the disease, according to Block.
He said a well-funded and well-resourced terrorist group that had access to the right scientific experts could potentially develop an Ebola weapon, but he doesn't see it happening.
"I consider it frankly to be a relatively unlikely scenario," he said. "But if you're asking me the narrow question, 'Is it technically feasible,' yes [it is]."
Stars and Stripes asked officials at DTRA if the agency is worried that terrorists or other actors hostile to the U.S. could potentially weaponize the virus.
"DTRA addresses threats posed by WMD. Threats can come from weapons as well as natural hazards, which is what we're dealing with now" with the latest Ebola outbreak, DTRA spokesman Dan Gaffney said in an email. "DTRA and other federal agencies continue to do research on Ebola and hemorrhagic fevers, in order to get ahead of any potential threat."
Stars and Stripes reporter Chris Carroll contributed to this report.