# When is a contagion "airborne" or "not airborne"?
**URL:** https://boards.straightdope.com/t/when-is-a-contagion-airborne-or-not-airborne/701412
**Category:** Factual Questions
**Created:** [October 15, 2014, 4:59pm UTC](https://boards.straightdope.com/t/when-is-a-contagion-airborne-or-not-airborne/701412 "2014-10-15T16:59:22Z")
**Posts on this page:** 13
**Page:** 1
### Author:  [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)
#### Post date: [October 15, 2014, 4:59pm UTC](https://boards.straightdope.com/t/when-is-a-contagion-airborne-or-not-airborne/701412/1 "2014-10-15T16:59:22Z")
The word of the day is that the Ebola virus is not prone to airborne transmission. OTOH, diseases like the flu _are_ prone to airborne transmission, specifically by coughs or sneezes that produce aerosols of virus-bearing mucus/saliva droplets.
So why can Ebola not be transmitted in this manner? I understand that coughing and sneezing aren’t specifically symptoms of an Ebola infection - but healthy people sneeze and cough from time to time, so I would expect someone infected with Ebola to cough and sneeze from time to time as well. Why would this not produce an infectious aerosol?
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### Author:  [@nizzle](https://boards.straightdope.com/u/nizzle)
#### Post date: [October 15, 2014, 5:02pm UTC](https://boards.straightdope.com/t/when-is-a-contagion-airborne-or-not-airborne/701412/2 "2014-10-15T17:02:20Z")
does coughing count as something being airbourne? If someone with ebola spits in my mouth does that count as airbourne? I always kinda assumed ‘airbourne’ meant if I was in a room with someone who was ill I could get it from the ‘air’ diffusing the virus around from their breath, not specifically their spit/mucus/sneeze. That was an assumption though on my part
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### Author:  [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)
#### Post date: [October 15, 2014, 7:12pm UTC](https://boards.straightdope.com/t/when-is-a-contagion-airborne-or-not-airborne/701412/3 "2014-10-15T19:12:34Z")
> [@nizzle](#):
>
> does coughing count as something being airbourne? If someone with ebola spits in my mouth does that count as airbourne? I always kinda assumed ‘airbourne’ meant if I was in a room with someone who was ill I could get it from the ‘air’ diffusing the virus around from their breath, not specifically their spit/mucus/sneeze. That was an assumption though on my part
See [“airborne disease.”](http://en.wikipedia.org/wiki/Airborne_disease) Airborne transmission is due to aerosols of dust or liquids. Liquid aerosols include those generated by coughing or sneezing; dust aerosols would include (for example) dried fecal material; this is how [hantavirus](http://en.wikipedia.org/wiki/Hantavirus#Transmission) is transmitted to humans.
I could be wrong, but I don’t think normal breathing generates liquid aerosols.
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### Author:  [@Senegoid](https://boards.straightdope.com/u/Senegoid)
#### Post date: [October 17, 2014, 1:28am UTC](https://boards.straightdope.com/t/when-is-a-contagion-airborne-or-not-airborne/701412/4 "2014-10-17T01:28:24Z")
There are just four hospitals in the Unites States that have full-fledged biocontainment units for the proper isolation and treatment of Ebola patients. Several of the Ebola patients have been transported, via air ambulance, to one or another of these.
So yes, Ebola is airborne.
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### Author:  [@dofe](https://boards.straightdope.com/u/dofe)
#### Post date: [October 17, 2014, 1:33am UTC](https://boards.straightdope.com/t/when-is-a-contagion-airborne-or-not-airborne/701412/5 "2014-10-17T01:33:52Z")
> [@Senegoid](#):
>
> There are just four hospitals in the Unites States that have full-fledged biocontainment units for the proper isolation and treatment of Ebola patients. Several of the Ebola patients have been transported, via air ambulance, to one or another of these.
>
> So yes, Ebola is airborne.
Since this is GQ, and the question is a factual one, would you care to provide a cite indicating that airborne transmission of Ebola has suddenly been proven to have occurred?
Edit: apologies if I sound annoyed – I’m just tired of the hysteria and the spread of false facts when it comes to ebola.
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### Author:  [@UDS](https://boards.straightdope.com/u/UDS)
#### Post date: [October 17, 2014, 2:16am UTC](https://boards.straightdope.com/t/when-is-a-contagion-airborne-or-not-airborne/701412/6 "2014-10-17T02:16:28Z")
It’s a feeble joke, dofe. Ebola patients have been carried in airplanes, therefore ebola is airborne. Geddit?
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### Author:  [@dasmoocher](https://boards.straightdope.com/u/dasmoocher)
#### Post date: [October 17, 2014, 2:16am UTC](https://boards.straightdope.com/t/when-is-a-contagion-airborne-or-not-airborne/701412/7 "2014-10-17T02:16:41Z")
> [@Machine\_Elf](#):
>
> I could be wrong, but I don’t think normal breathing generates liquid aerosols.
From this virology blog ([Transmission of Ebola virus](http://www.virology.ws/2014/09/27/transmission-of-ebola-virus/)):
> [@](#):
>
> All of us emit aerosols when we speak, breathe, sneeze, or cough. If we are infected with a respiratory virus such as influenza virus, the aerosols contain virus particles. Depending on their size, aerosols may travel long distances, and when inhaled they lodge on mucosal surfaces of the respiratory tract, initiating an infection.
>
> Viral transmission can also occur when virus-containing respiratory droplets travel from the respiratory tract of an infected person to mucosal surfaces of another person. Because these droplets are larger, they cannot travel long distances as do aerosols, and are considered a form of contact transmission. Ebola virus can certainly be transmitted from person to person by droplets.
An analogy I’ve heard about the difference between airborne droplets and aerosols is that a parachutist is “airborne” but rapidly descending (like a droplet), while a hang glider can stay aloft for a great deal of time and distance (aerosol).
Here’s the Microbe Wiki on [Infection Mechanism of Genus Ebolavirus](https://microbewiki.kenyon.edu/index.php/Infection_Mechanism_of_Genus_Ebolavirus).
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### Author:  [@WhyNot](https://boards.straightdope.com/u/WhyNot)
#### Post date: [October 17, 2014, 2:25am UTC](https://boards.straightdope.com/t/when-is-a-contagion-airborne-or-not-airborne/701412/8 "2014-10-17T02:25:01Z")
Three feet.
If something is carried in a big heavy droplet that moves fewer than three feet from the patient (like spittle or mucus from a cough or sneeze), and then drops, then it’s Droplet borne.
If something is carried in a fine mist so that it can move further than three feet and is so small and light that it doesn’t immediately drop to the nearest horizontal surface below, it’s Airborne.
Thus sayeth nursing school, anyhow. I’m too tired to go look for a cite.
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### Author:  [@dofe](https://boards.straightdope.com/u/dofe)
#### Post date: [October 17, 2014, 2:43am UTC](https://boards.straightdope.com/t/when-is-a-contagion-airborne-or-not-airborne/701412/9 "2014-10-17T02:43:29Z")
> [@UDS](#):
>
> It’s a feeble joke, dofe. Ebola patients have been carried in airplanes, therefore ebola is airborne. Geddit?
:smack:😃
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### Author:  [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)
#### Post date: [October 17, 2014, 12:15pm UTC](https://boards.straightdope.com/t/when-is-a-contagion-airborne-or-not-airborne/701412/10 "2014-10-17T12:15:04Z")
> [@WhyNot](#):
>
> If something is carried in a fine mist so that it can move further than three feet and is so small and light that it doesn’t immediately drop to the nearest horizontal surface below, it’s Airborne.
If large droplets (that can’t get more than 3’ away before settling) can carry Ebola, why wouldn’t small droplets that remain aloft also be infectious?
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### Author:  [@WhyNot](https://boards.straightdope.com/u/WhyNot)
#### Post date: [October 17, 2014, 12:47pm UTC](https://boards.straightdope.com/t/when-is-a-contagion-airborne-or-not-airborne/701412/11 "2014-10-17T12:47:24Z")
> [@Machine\_Elf](#):
>
> If large droplets (that can’t get more than 3’ away before settling) can carry Ebola, why wouldn’t small droplets that remain aloft also be infectious?
Don’t know. But it’s fairly common for non-respiratory viruses, like HIV. My (slightly educated) guess is that small droplets that remain aloft aren’t produced unless the lungs are making that kind of secretion, and that kind of secretions are produced during respiratory infections, but not during non-respiratory infections.
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### Author:  [@WhyNot](https://boards.straightdope.com/u/WhyNot)
#### Post date: [October 17, 2014, 1:36pm UTC](https://boards.straightdope.com/t/when-is-a-contagion-airborne-or-not-airborne/701412/12 "2014-10-17T13:36:16Z")
I realized that last post could be misinterpreted as meaning that HIV is spread by droplets, which is not true. I used it only as a well known example of a virus which is not airborne. HIV requires only Standard or Universal precautions, hand washing and gloves when contact with bodily fluids is anticipated. Sorry if I confused or alarmed anyone.
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### Author:  [@dasmoocher](https://boards.straightdope.com/u/dasmoocher)
#### Post date: [October 17, 2014, 2:03pm UTC](https://boards.straightdope.com/t/when-is-a-contagion-airborne-or-not-airborne/701412/13 "2014-10-17T14:03:20Z")
> [@Machine\_Elf](#):
>
> If large droplets (that can’t get more than 3’ away before settling) can carry Ebola, why wouldn’t small droplets that remain aloft also be infectious?
From the virology blog I linked to above:
> [@](#):
>
> We do not know why, in humans or non-human primates, Ebola virus does not transmit by respiratory aerosols. The virus might not reach sufficiently high titers in the respiratory tract, or be stable in respiratory secretions, to be efficiently transmitted by this route. There are many other possibilities. A careful study of Ebola virus titers in the human respiratory tract, and in respiratory secretions, would be valuable. However during Ebola virus outbreaks the main concern is to save people, not conduct experiments.
and
> [@](#):
>
> In the laboratory, machines called nebulizers (which are used to administer medications to humans by inhalation) can be used to produce virus-containing aerosols for studies in animals. A human would likely be infected with an Ebola virus-containing aerosol generated by a nebulizer (theoretically; such an experiment would be unethical).
Yeah–unethical. We’re kinda limited when designing experiments to study Ebola in humans.