From:
http://commonhealth.wbur.org/2014/10/reality-check-how-catch-ebola
A question/answer session with an actual Ebola expert. Dr. Elka Muhlberger. I recommend reading the whole thing before posting panicked bits and pieces of hysteria.
Some people are claiming that to infect so many people, the virus must have moved from just bodily fluids to “airborne”…
I think there’s some confusion here. We know that some viruses — like influenza virus, and measles — are transmitted before the patient shows symptoms. Especially the measles virus, which is the winner in terms of being contagious. What these viruses do is infect the respiratory tract — that is their first target organ. That’s how they start the infection, and then they replicate or amplify themselves in cells of the upper respiratory tract. And then when we breathe, we release these viruses because they’re part of our ‘breathing air.’ There are tiny, tiny, tiny little droplets, and these droplets contain the virus. They can stretch pretty far, like a couple of feet. And that is what we call an airborne infection. If we breathe and then we shed virus with our breath.
So you don’t even need visible droplets, it’s just air?
They’re tiny little droplets in our breath. And these viral particles are part of it. This is completely different from Ebola virus. First of all, Ebola virus does not begin an infection by infecting our upper respiratory tract. The route of infection starts with little lesions in our skin, and then the virus gets in our skin, and then in our blood system, and then in these immune cells I mentioned before, which are the primary target cells. It’s also able to get into our eyes and mucosal membranes, but it does not infect the cells which we need to get infected to have an infection be airborne. Late in the infection, when the Ebola virus patients have very high viral loads, they are really really ill, way too ill to get on a train and sit there.
So you’re saying that when they’re so ill that it could be in the respiratory system, they’re super-ill, not able to go anywhere?
Exactly. The cells in the lung can be infected by Ebola virus but really late in the infection. That’s very important. As far as we know, the infection starts with the immune cells — for those who know a little more about the immune system, it’s dendritic cells and macrophages. Then it goes to lymph nodes. Then very quickly to the liver, and there it goes crazy. The liver is very crucial in Ebola virus infections because it is so heavily affected. Ebola virus also spreads to the spleen, to other organs, and then later in infection it tends to infect the cells that coat the blood vessels, and of course we have these cells in the lung as well.
So when we are infected with Ebola virus and we are really sick, then we spread the virus through all our body fluids, which includes blood, sputum, feces urine, breast milk and semen. Again, then we have Ebola virus in little droplets, which is the reason we talk about infection via droplets, but these droplets are much bigger — though they are tiny, of course — but these are much bigger than the droplets which cause aerosol-borne disease. So it’s a matter of size. And if they are bigger they cannot be transmitted over a large distance.
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