New paper on Ebola--no primate-to-primate transmission seen

By the same lead author that published the pig Ebola transmission paper comes a new publication examining airborne transmission among primates. In these, Ebola did *not* spread between non-human primates (NHPs) via air. I sent an email to the PI to comment; will update the post if he responds, but in the meantime, some money quotes directly from the publication:

"One experiment reported contact free transmission between infected NHPs to one uninfected NHP although cross-contamination due to husbandry practices could not be ruled out with certainty26. Interestingly, EBOV infected swine transmitted the virus to naïve NHPs over a 0.3 meter buffer zone that prevented direct contact between the 2 species27. ...However, airborne transmission in natural outbreaks cannot be a common occurrence and is possibly insignificant by the account of several reports49282930."


"The presence of transmission in the pig-NHP experiment and not the NHP-NHP experiment, both performed under similar conditions and environments, could be explained by the fact that EBOV disease in pigs is respiratory in nature with high amounts of infectious particles present in the oro-nasal cavities in the symptomatic phase of the disease which provided an opportunity for release into the environment35. On the receiving end, NHPs are known to be susceptible to lethal EBOV infection through the respiratory tract242731 putting the onus of the transmission on the ability of the source to shed infectious particles."

Translation: even though previous reports in primates had suggested the potential for airborne transmission, other factors couldn't be ruled out, and epidemiologically, it's insignificant. In the experiments they did, pigs just handle Ebola differently than primates (as I mentioned here), and so make them more likely to spread the virus via a respiratory route.

Significance: No airborne transmission between primates in this controlled experiment, strengthening the evidence that Zaire ebolavirus isn't a risk in this manner. So Donald Trump, you can stop freaking out now.

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Did they do tests with the Ebola Reston variety? In its orignal outbreak in Reston, it showed some signs of spreading by airborne transmission.

By John Yesford (not verified) on 09 Aug 2014 #permalink

Ebola Zaire is transmitted in body fluids including saliva and nasal mucous. A cough or sneeze broadcasts those droplets. So technically, there may be no transmission in controlled studies. But if you get Ebola Zaire droplets on your hand from a sneeze or cough, and touch your face, you will most likely contract Ebola. This report may tend to minimize a very viable threat of transmission.

By Indiana Mike (not verified) on 09 Aug 2014 #permalink

Indiana Mike@ 2: Technically, that is not airborne transmission; that is fomite or aerosol transmission. So, yes, that material gets into the air, and you could get it on you from the air, but the droplet sizes are pretty big (relatively speaking) so they would tend to fall to the ground pretty rapidly. Another thing is that the lungs are not the mode of transmission - it's mucus membranes.

So in the situation you describe, as long as you *don't* touch your face, change your gloves and wash your hands, you would probably be OK.

It's still very dangerous, but it's not like measles, where being at the same elevator where an infectious person was 10 minutes ago can lead to infection.

Good discussion!

By JustaTech (not verified) on 11 Aug 2014 #permalink

If aerosol transmission is not considered technically the same as airborne transmission, then that is some very fine hair splitting. Not that I have anything against such, but it does mean people have to be very exactly clear about what they mean by airborne transmission. I think this has caused a lot of confusion on this issue.

Anyway, you have to like this one from that Trump story link:

"I hope that our understandable fear of the unfamiliar does not trump our compassion when ill Americans return to the U.S. for care," said Dr. Tom Frieden...

Pun intended I would imagine.

By Jim Bouldin (not verified) on 14 Aug 2014 #permalink

Below is an excerpt from a news article about a hospital worker in Monrovia who recently died from ebola. At this point, whether this is an airborne variant of ebola, or a super-contagious strain that can be spread through mere touch, seems to be a meaningless distinction.

"She caught Ebola at work, at the Catholic Hospital here in Monrovia. The hospital administrator had got ill.
He tested positive for Ebola.
It was my wife’s job to give him an ECG examination, to put the pads on his body.
She knew she had to put plastic gloves on, but for a few seconds she was touching him with her hands, to help him get off the bed and on to a chair.
That is how she got it."…

By TJ Harvey (not verified) on 18 Aug 2014 #permalink

What makes ebola different from other viruses that prevents airborne transmission in primates? Is it the fact that it doesn't attack the lungs? Or is there a physical limitation to the virus that provides the reason?
I haven't seen any explanation about why it isn't possible. While I believe you and the research many Americans won't. Perhaps addressing the fears by explaining why it isn't possible is the most effective messaging tool. Provide comparisons with Measles (airborne transmission) and HIV (not airborne).