The question often asked is whether Ebola could evolve to spread through the air in dried particles, entering the body along a pathway into the lungs. Eric Lander, the head of the Broad Institute, thinks that this is the wrong question to ask. Lander is tall, with a square face and a mustache, and he speaks rapidly and with conviction. “That’s like asking the question ‘Can zebras become airborne,’ ” he said. In order to become fully airborne, Ebola virus particles would need to be able to survive in a dehydrated state on tiny dust motes that remain suspended in the air and then be able to penetrate cells in the lining of the lungs. Lander thinks that Ebola is very unlikely to develop these abilities. “That would be like saying that a virus that has evolved to have a certain life style, spreading through direct contact, can evolve all of a sudden to have a totally different life style, spreading in dried form through the air. A better question would be ‘Can zebras learn to run faster?’ ”
There are many ways by which Ebola could become more contagious even without becoming airborne, Lander said. For example, it could become less virulent in humans, causing a milder disease and killing maybe twenty per cent of its victims instead of fifty per cent. This could leave more of them sick rather than dead, and perhaps sick for longer. That might be good for Ebola, since the host would live longer and could start even more chains of infection.
