Scientists have reached a surprising level of consensus on the appropriate response to the West African Ebola epidemic, despite the appearance of bitter disputes and wild pendulum swings in the media.
In August, CBS Atlanta and the Associated Press reported that the epidemic was “Spinning out of Control”, Slate said it was “Spiraling Out of Control,” at the same time Bloomberg News listed “Five Threats More Terrifying than Ebola Entering the U.S.”, including the threat of a giant electromagnetic pulse.
The perception of discord among experts worsened after epidemiologist Michael Osterholm of the University of Minnesota wrote an opinion piece for the September 11 New York Times noting that the Ebola virus is evolving and that there’s a remote but real possibility it would acquire a more efficient way to spread among humans – even an airborne route. Quickly Time and Scientific American responded with stories quoting other scientists saying this would not happen. Those counterarguments were echoed in the Washington Post and other media outlets.
And yet, scientists are more or less in agreement that there are big unknowns and that the West African outbreak calls for serious and swift action. Getting the straight story is of enormous importance now that a man from Liberia came down with Ebola symptoms in Texas and health officials are tracking down dozens of people who may have had contact with him while he was potentially contagous.
Despite the backlash that followed Osterholm’s New York Times opinion piece, other scientists agree with his key points, which were that the world should devote resources to containing the epidemic in West Africa, that there’s a lot of uncertainty about the future, and that the uncertainty gives us more incentive to act. “…we are in totally uncharted waters and…mother nature is the only force in charge of the crisis at this time.”
Steven Morse, an epidemiologist at Columbia University, said all the furor over Osterholm’s speculation on airborne spread has overshadowed a more important and serious point in his editorial: The virus is evolving, it will evolve faster as the number of cases mushrooms, and it may acquire mechanisms to spread more easily than it does at the present time.
Still, the Times piece contained a few statements that other scientists called out as misleading, including the notion that should Ebola become airborne, “Infections could spread quickly to every part of the globe, as the H1N1 influenza virus did in 2009.” Maybe, but probably not, say some critics.
The editorial started out on the wrong track by using the headline, “What we’re Afraid to Say about Ebola.” That suggests a level of collusion and secrecy among scientists for which he offers no evidence in the piece.
The piece that followed in Scientific American, too, suffers from a bad headline: True or False, Ebola Will Go Airborne. That’s like saying True or False, there will be a major earthquake in Los Angles next Wednesday. It’s not only nonsensical, but encourages a fallacious black-or-white thinking about an issue of probabilities and risks.
(Note to Scientific American editors: A Google search yields the following: “The Ebola Virus Will Go Airborne – Scientific American.” The truncated headline gives a message that undermines the point of the story.)
The story’s author explains in some technical detail why it’s next to impossible for the virus to get into cells in the airway, quoting Vanderbilt University infectious disease expert William Schaffner, who said the virus isn’t equipped to attach to receptors in the cells that line our airways.
But Dr. Schaffner does not do research in this area. Biologist David Sanders at Purdue University does. In fact, Sanders conducts experiments with modified Ebola viruses and tissue cultures and he said he has seen direct evidence that Ebola does have the capacity to attach to receptors in the so-called epithelial cells in human lungs. “Saying that Ebola can’t get into the airway because it can’t find the receptors is patently wrong,” he said. “We know Ebola has the correct interactions with the receptors so the sort of argument they are making is fallacious.”
Sanders explained that the cells lining our lungs, called epithelial cells, are separated from one another by two membranes – the basolateral membrane, which interfaces with the bloodstream, and the apical membrane, which interfaces with the outside environment. HIV moves out through the basolateral membrane, while influenza moves in and out through the apical membrane.
That means HIV is extremely unlikely to become airborne because it can’t move through the appropriate membrane. Sanders puts the risk at essentially zero. Not so for Ebola, since his experiments show it can get through the apical membrane. That doesn’t mean it’s likely to evolve the capacity to become airborne, he said, but the possibility is not vanishingly small as it is for HIV. How unlikely? Not enough is known to put a number on it.
But even if the virus did become airborne, it might not spread rapidly that way, he said. The ability to do that depends on many factors, including how long it can survive on surfaces, viral concentrations in epithelial cells, and other unknown factors. In some cases, such as anthrax, the symptoms and severity of the disease differs depending on whether it’s inhaled or acquired through a cut in the skin.
Vanderbilt’s Schaffner, who was quoted in Scientific American, said he was not familiar with Sanders’ papers, and that the nitty gritty of viruses interacting with cell membranes was not his specialty. The other expert in the story, Thomas Geisbert of the University of Texas Medical Branch at Galviston, was quoted saying something that echoed Sanders: “I don’t think we have the information at this time to know what the real risk is, but it is probably not zero.”
Despite any perceived disagreement, many experts seem to have found consensus on the main point – appropriating resources now could avert a much worse situation in the future due to the exponential spread of the disease and its undisputed capacity for evolution in directions that can’t be forecast. The main difference seems to be over the reasons behind the call for action. There’s the obvious one – people are dying in West Africa. Should the remote possibility of a wider spread be included too? This is a minor point of disagreement.
Dr. Osterholm, in his Times editorial, backs the sentiment of Penn’s Harvey Rubin in calling for an international organization devoted to responding to infectious disease outbreaks. He suggests a more concrete role for the United Nations – a course of action that hardly smells of panic.
Morse, the epidemiologist from Columbia University, put it in more concrete terms. Though he admits he’s delving into politics, he sees the situation as serious enough to warrant sending U.S. troops into the heart of the outbreak to help. There’s a lot the military can do, he said, including getting hospitals enough potable water.
And yet, as deployments go, fighting Ebola is relatively safe, he said. The military has the equipment for facing biological and chemical threats, he said, and so they can do a lot of good with relatively little risk of getting killed.
Scientists should be open about risk and uncertainty. They won’t incite hysteria as long as they are clear about separating fact from hypothesis from speculation. And they need to provide enough context and interpretation to avoid being misconstrued as either too alarmist or too complacent. Neither extreme will serve the world well.
Source: Forbes