Ebola virus may be spread by droplets, but not by an airborne route: what that means

[uppityperson]

Please read the entire post at the link as there is other important information there that I am limited from posting due to copyright rules.

http://virologydownunder.blogspot.com/2014/08/ebola-virus-may-be-spread-by-droplets.html

A variant Ebola virus belonging to Zaire ebolavirus (EBOV) is active in four West African countries right now. Much is being said and written about it, and much of that revolves around our movie-influenced idea of an easily spread, airborne horror virus. Many people worry about their risks of catching EBOV, particularly since it hopped on a plane to Nigeria. However, all evidence suggests that this variant is not airborne. The most frequent routes to acquire an EBOV infection involve direct contact with the blood, vomit, sweat or stool of a person with advanced Ebola virus disease (EVD). But what is direct contact? What is an “airborne” route? For that matter what is an aerosol and what role do aerosols play in spreading EVD? How is an aerosol different from a droplet spray? Can droplets carry EBOV through the air?

Direct contact includes physical touch but also contact with infectious droplets; the contact is directly from one human to the next, rather than indirectly via an intermediate object or a lingering cloud of infectious particles. You cannot catch EVD by an airborne route, but you may from droplet sprays. Wait, what?? This is where a simple definition becomes really important.



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For EBOV at least, airborne droplet nuclei are apparently not infectious to primates under natural or near-natural circumstances (see here for more detail about non-human primates and aerosols used under highly unnatural laboratory conditions). Why that is so is not known, but perhaps it is because this virus does not survive being dried down, or that primates don’t produce enough virus in what is coughed out to make infectious droplet nuclei. To be clear, there may be some EBOV in these droplet nuclei - but it has never been shown to cause disease, even when that route has been looked for in the same household as a case of EVD.

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Included in guidelines issued by the WHO (7) and CDC (5) is the need for droplet precautions (Figure). This is very important for healthcare workers, family and other caregivers who stay close and are frequently exposed for lengthy periods of time with severely ill, highly virulent cases of EVD. These cases may actively propel infectious droplets containing vomit and blood across the short distances separating them from caregivers. But this is a form of direct transmission, and is not airborne transmission....(more)

[MohRokTah]

1. So that means two things must happen

First, you must be within 1 meter of an unprotected sneeze or cough for the possibility of transmission.

Second, droplets from the sneeze or cough must come into contact with the nose, eyes, mouth, or an open wound for the possibility of transmission.

[morningfog]

2. Not only that, the virus becomes more contagious

as it builds in the body. So even if a sneeze is closely sprayed into your mouth, if the infected person is early in showing symptoms it wouldn't likely infect.

[BlindTiresias]

4. Wrong

Ebola requires only 1-10 virus particle to induce infection, making it in the same realm of infectivity as Norwalk virus.

If you are outside of the droplet zone you are fine, if you are within it you are in danger.

[morningfog]

6. Not as much danger early on. Jesus Christ.

This is the most obnoxious story to discuss since Y2k.

[BlindTiresias]

8. Marginal reduction at best

Smaller viral load does mean less shedding, but if the amount of virus particles needed to induce infection is also small it doesn't make much difference.

[uppityperson]

9. Link to that please? thank you.

[morningfog]

11. Here:

http://www.democraticunderground.com/?com=view_post&forum=1002&pid=5605676

Post #102

[uppityperson]

12. Thank you. I am distrusting everything unless can source it as too much misinformation and playing

telephone happening.

I like this quote
“The issue is not that Ebola is highly infectious. The issue with Ebola is that the stakes are so high. People are infectious with Ebola when they are sick.”

And I found what you meant
http://www.nbcnews.com/storyline/ebola-virus-outbreak/what-we-know-about-texas-ebola-patient-n215451

People do not infect others after they get better, and they do not seem to always be particularly infectious early on in the disease — when they first get a fever, for example. The virus has to build up in the body. The most infectious people are those just about to die or who have just died, which is why burying Ebola victims is especially dangerous.

[Turborama]

22. And here...

http://www.democraticunderground.com/?com=view_post&forum=1002&pid=5605960

[uppityperson]

23. Thank you for the information from WHO. Copied here.

http://www.who.int/ith/updates/20140421/en/

Summary of epidemiological facts and experience

The incubation period of Ebola virus disease (EVD) varies from 2 to 21 days. Person-to-person transmission by means of direct contact with infected persons or their body fluids/secretions is considered the principal mode of transmission. In a household study, secondary transmission took place only if direct physical contact occurred. No transmission was reported without this direct contact. Airborne transmission has not been documented during previous EVD outbreaks.

There is no risk of transmission during the incubation period and only low risk of transmission in the early phase of symptomatic patients. The risk of infection during transport of persons can be further reduced through use of infection control precautions (see paragraphs 3.2 and 3.3).

[uppityperson]

3. Yes.

Or the person could have explosive diarrhea or vomiting or bleeding, AND you'd have to be within range AND get the droplets in contact with mucous membrane or open wound.

[Orrex]

5. I'll be on the lookout for people coughing up red circles

Wait--is that an Indigo? I knew it!

[uppityperson]

7. Watch for crop circles made of kale.

[freshwest]

14. And rainbow-colored Swiss Chard:

Swiss Chard

The stems of Swiss chard look a little like celery and can be green, red or rainbow-colored- a mixture of red, pink, orange and yellow. In the ‘greens’ family, Swiss Chard belongs to the same family as beets and spinach and shares a similar taste profile: it has the bitterness of beet greens and the slightly salty flavor of spinach leaves. These greens also rank very high in nutritional value as they are fat free, cholesterol free, good source of magnesium, excellent source vitamins A and C.

Good in smoothies.

[NightWatcher]

10. I should probably stop licking people in the mall food court too, so far I've only gotten a cold,

three restraining orders, and seventeen phone numbers.

[Jamastiene]

30. You owe me a new keyboard.

[boomer55]

13. slow motion sneeze on video by mythbusters...

http://www.discovery.com/tv-shows/mythbusters/videos/slow-motion-sneezes.htm

[Jamastiene]

31. They didn't happen to mention what the farthest distance was for their tests, did they?

My aunt swears up and down that sneezes travel at 35 mph and go practically miles from the sneezer. I have always wanted to know the true stats on that.

Btw, that was gross, just like they said, when they played the video backward.

[uppityperson]

15. Another article about transmitting the virus.

http://www.npr.org/blogs/goatsandsoda/2014/09/12/346114454/how-do-you-catch-ebola-by-air-sweat-or-water

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Note: A study in 2012 showed infected pigs passed on the Ebola to monkeys without touching them. Besides the fact that people aren't pigs or monkeys, the lead author has pointed out it's possible the monkeys caught the virus when droplets from the pigs splashed into their cage during cleaning.
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The virus is most abundant in blood and diarrhea. In fact, a milliliter of blood typically carries about a million infectious particles. And in a controlled lab, just a small drop of blood from an infected monkey can be strong enough to kill a million of its companions, Schmaljohn says.

A CDC study in 2007 found that Ebola is shed through other bodily fluids during the illness, such as saliva, breast milk and semen. In most cases, these fluids were not visibly contaminated by blood, but they still contained the virus. That study didn't look at sweat, but another one suggested that Ebola could be passed on through sweat. Researchers suspect the amount of Ebola in these other fluids, like saliva and sweat, to be much lower.

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A drop of blood can remain contagious outside the body. And virus particles can survive for days or weeks, depending on the environment. Ultraviolet light, heat and exposure to oxygen gradually deactivate the virus, while cooler temperatures and humidity help keep it active.

[Baitball Blogger]

16. Thanks for the information uppity!

[uppityperson]

17. You are welcome. It is a scary disease in that the mortality rate is so high, is good to research

and find out about the infection process. The more I read, the more it is making sense and while the disease itself, the process, is amazing, it is also less frightening overall.

It makes blood clots inappropriate places which hurt organs and all sorts of places, using up clotting factor, leading then to lack of clotting, increased bleeding including bruising all over. Because of the blood clots, organs die (liver, kidneys). Rather DICish (Disseminated intravascular coagulation), something I ran across many years ago when first became a nurse.

http://www.bu.edu/today/2014/how-ebola-kills/

Another thing we are looking at is what goes wrong with the immune response during viral infection. Our bodies are so good at responding to so many diseases, and in most cases we get sick for a couple of days and then we get better. Our response to Ebola is totally out of whack. The immune system appears to deliver a much more aggressive response than is necessary, one that causes a lot of damage to the body. That overreaction is a significant part of what makes infection with this virus so deadly.

What kind of damage is done by the overreaction?
The response is so strong that it triggers other pathologies. This can include diffuse intravascular coagulopathy, which is why the virus is often called a hemorrhagic fever virus. Normally, coagulation is constantly serving your body, so if you get cut you get a nice blood clot that seals you up. It’s a great way to keep your blood from leaking out. In the case of Ebola, you get clotting in inappropriate places, such as organs like the liver. The problem is, you have a finite number of clotting factors in your body, and they get depleted from the inappropriate clotting. When that happens, you have a hole in your body that needs clotting but won’t stop bleeding. All the small things that happen on a daily basis that are normally taken care of by coagulation are not working.

[Baitball Blogger]

20. It does sound like our immune systems are not equipped to handle it properly.

Let's hope the CDC does a good detective job of hunting down everyone who may have come in contact with patient 0 to make sure they are all right.

[librechik]

18. use common sense and remember your history

the great flu epidemic of 1919 spread because of poor sanitation in cities, which let's just say we don't have here.

The other way is mass transit. If it starts to spread in urban areas, put on your gloves and mask before getting on the subway or bus, like they do in China.

We'll have to learn how to live with it like we live with flu or malaria or MRSA.

[uppityperson]

19. Indeed. Here is a look at a Sierra Leone hospital, very different from here.

http://www.democraticunderground.com/10025608499
http://www.nytimes.com/2014/10/02/world/africa/ebola-spreading-in-west-africa.html?_r=0

MAKENI, Sierra Leone — “Where’s the corpse?” the burial-team worker shouted, kicking open the door of the isolation ward at the government hospital here. The body was right in front of him, a solidly built young man sprawled out on the floor all night, his right hand twisted in an awkward clench.

The other patients, normally padlocked inside, were too sick to look up as the body was hauled away. Nurses, some not wearing gloves and others in street clothes, clustered by the door as pools of the patients’ bodily fluids spread to the threshold. A worker kicked another man on the floor to see if he was still alive. The man’s foot moved and the team kept going. It was 1:30 in the afternoon.

In the next ward, a 4-year-old girl lay on the floor in urine, motionless, bleeding from her mouth, her eyes open. A corpse lay in the corner — a young woman, legs akimbo, who had died overnight. A small child stood in a cot watching as the team took the body away, stepping around a little boy lying immobile next to black buckets of vomit. They sprayed the body, and the little girl on the floor, with chlorine as they left.

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But little of that help has reached this city. The dead, the gravely ill, those who are vomiting or have diarrhea, are placed among patients who have not yet been confirmed as Ebola victims — there is not even a laboratory here to test them. At one of the three holding centers in Makeni, dazed Ebola patients linger outside, close to health workers and soldiers guarding them. The risk of infection is high, the precautions minimal.

[Turborama]

21. K&R Thank you for posting these very informative explanations n/t

[Turborama]

24. CDC: Can Ebola spread by coughing? By sneezing?

Unlike respiratory illnesses like measles or chickenpox, which can be transmitted by virus particles that remain suspended in the air after an infected person coughs or sneezes, Ebola is transmitted by direct contact with body fluids of a person who has symptoms of Ebola disease. Although coughing and sneezing are not common symptoms of Ebola, if a symptomatic patient with Ebola coughs or sneezes on someone, and saliva or mucus come into contact with that person’s eyes, nose or mouth, these fluids may transmit the disease.


More Q&As here: http://www.cdc.gov/vhf/ebola/transmission/qas.html

[LeftyMom]

25. Good luck explaining this to the panic people. I fucking give up.

BETTER SHIT TO DO.

[uppityperson]

26. Thanks for helping, I am getting close too.

[ecstatic]

29. FYI--Not everyone who is mad or angry is panicking

I'm not panicking. I just don't think enough precautions are being taken to make sure infectious people aren't walking around. I don't get the blind faith some people have in our system (even after glaring weaknesses are revealed). As they say, "Pride comes before the fall."

I also think Mr. Duncan's actions were incredibly selfish. The best way to infuriate me is to cause harm to a child, and Mr. Duncan put at least 5 kids' lives at risk.

[scarletwoman]

27. Thanks so much! I really appreciate the efforts you've been making

to bring reason into the DU conversation about ebola.

I'm just amazed to witness the way some DUers seem to be freaking out. It's like some people want this to be the Zombie Apocalypse or something.

[Eleanors38]

32. You noticed, too.

[jberryhill]

28. I'm going to stay away from large dark blue people, for sure!

[Eleanors38]

33. Yes, you may be phlegm-flammed by them.