He has a reputation on the line, for good or ill. In some circles your reputation can make you or break you, professionally.
It would be decidedly uncharacteristic for a Medical Doctor to stick his professional neck out and say the CDC was recommending insufficient PPE for medical personnel unless he or she had darned good reason to believe they were correct and unless he or she could lay out evidence to that effect.
The doctor laid out his evidence. What is yours to the contrary?
I have to go back to what I said about his evidence. He used evidence that did not prove his allegations. So his conclusion was just conjecture off the top of his head where he intentionally (being a doctor) misapplied the term “airborne” and conflated it with “casual”.
That’s what he did, and that’s my evidence.
Just to be clear, in this article they reference a test where they tested "aerosol' infection routes and using Ebola Zaire in primates, they determined that the "aerosol" or small particle spray of infection containing mucosa or fluids, had a virus load that was enough to infect the primates tested. The term "aerosol" does not mean airborne unless it specifically says so. It does not delinieate that the radius or distance from a infected patient, primate or human, can be small,large or unlimited in the real world. Aerosols, as you can exhibit and test for yourself at home with a spray bottle, do not travel far without assistance from wind or some other natural or artificial aid. And as mentioned in that doctors report, these aerosols can easily deposit virus on nearby surfaces. And aerosols do not mean exhaled breath. (I see no testing in this regard)
There have been no tests of the distances, however it is a fact that flu has this same transmission ability as do other viruses and the experiments were done with fairly close distances between cages..they were not testing for distance, only the viral load/aerosol "via aerosols") So in no case can I find the word "airborne" used with these aerosol infections or "liquid spray" It is still considered to be direct contact with excretions of the infected and why eye protection and masks and gowns are used as protection.
Now you could run some tests as to how a human might aerosolize their excretions, and how small a particle is created, and exactly what protection should be used for that, but I have never seen that research, so I believe what they do act with a abundance of caution with appropriate filter sizes and decontamination of surfaces on a regular basis in any area when infected patients are cared for or were known to have been.
But the term "airborne" carries with it certain connotations in that like a gas, or dust, the contaminant can hang in the air for hours and travel with the wind or simply precipitate where it wants to. It appears to me, reading all this literature, that the term "airborne" is a word that came from a Hollywood movie, decades ago.
They are not saying this in any of these experiments or tests. The purpose of the experiment was only to show that a small particle could carry a large enough virus load to infect.
Here is the quote:
Close or direct contact with the infected blood, secretions, organs or other bodily fluids appears to be the most likely source of infection of Reston ebolavirus and other Filoviruses. Bodily fluids of concern include: • Faeces – Reston ebolavirus has been detected in the epithelial cells of the gut mucosa in infected primates. Marked ulceration of gut mucosa has been noted during autopsies of infected non‐human primates indicating that viral shedding in faeces is likely; • Blood – evidence from other Filoviruses indicates that contact with infected blood can result in transmission; • Urine ‐ evidence from Filovirus infection in humans and monkeys indicates that the virus is excreted in urine; • Respiratory tract – no experimental inoculation has been performed for Reston ebolavirus. However, respiratory spread between non‐human primates is thought to have occurred during the 1989/90 outbreak in Reston, USA. Of note, experimental infection by aerosol route with Zaire ebolavirus has demonstrated that small particle aerosols are infectious at very low doses. Possible routes of entry include: • Inoculation. • Conjunctival/ocular mucosa – this has been demonstrated for Zaire ebolavirus in guinea pigs but no laboratory experiments have yet been performed for Reston ebolavirus. • Oral infection – this has been demonstrated for Zaire ebolavirus in monkeys but no laboratory experiments have yet been performed for Reston ebolavirus. • Respiratory – see above. Answer 6d: There is conclusive evidence that non-human primates can transmit Reston ebolavirus to humans. The most likely route of transmission is by direct contact with the blood, secretions, organs or other bodily fluids of infected animals. Possible routes of entry include inoculation, conjunctival contact and possibly inhalation.
Aerosol:
“A substance consisting of very fine particles of a liquid or solid suspended in a gas. Mist, which consists of very fine droplets of water in air, is an aerosol. Compare emulsionfoam”
Airborne:
“airborne transmission - a transmission mechanism in the which the infectious agent is spread as an aerosol and usually enters a person through the respiratory tract
transmission mechanism - any mechanism whereby an infectious agent is spread from a reservoir to a human being”
Without any limitations on distance of travel, the term is misleading, frankly, neither does the term aerosol limit the range, but a human being is not a atomizer, or nebulizer machine, and the distance that a aerosol created by a human is limited to particle size and what it’s suspended in.
In none of these tests or experiments, is the distance a part of the testing. The one test I did read, it was about three feet, which I would say is well within the range that a animal or human can project aerosol spray. I have seen animals spit at least ten feet, and humans can do three feet easily just by talking. I think they are just using common sense.
In addition, the respiratory tract or portions of it, including mouth and throat do seem to be involved in the transmission of Ebola as indicated by the WHO report, but it’s clearly shown that the eyes are as well and a typical way would be hand to mouth or finger to eye, even if gloved.
Proximity without a mask may also be a transmission method and that is what I believe they showed with the monkey test.
But for a doctor to chastise the CDC, essentially saying that they are lying to people because they did not use the term “airborne’ is utterly shameless in my view as the term Aerosol, covers that aspect in the case of Ebola and many other viruses.
I think he is begging for attention.
An article which may point to weaknesses in the presumed safety practices in this New Ebola outbreak.
http://newsoffice.mit.edu/2014/coughs-and-sneezes-float-farther-you-think
Includes high speed video to show effects and longer distance than previously thought possible, thus calling into question the current “safe droplet separation distance” with regard to the spread of pathogens.
With New Ebola presenting flu like symptoms, including coughing and sneezing, it now appears as if virally loaded droplets may pass beyond the rule of thumb 3 foot contact zone for greater projection leaving traces on surrounding surfaces. And those distances are remarkably longer than suspected. In very dense populations such as the West Point quarantined zone, the narrow passages insure constant bumping and brushing against against sweaty neighbors and confining surfaces.
Skins swabs of non PPE wearing HCWs might be in order to test for the presence of EV.
The MIT study might also apply to the hand spraying of bleach solutions. Turbulence from the spray may lift deposited droplets into the ambient air before bleach solution makes contact. Total immersion into the bleach solution might make better sense.
As with any battlefield medicine, field expediant techniques may outpace laboratory testing without full understanding of why they work.
(Excerpt)
he paper, “Violent expiratory events: on coughing and sneezing,” was published in the Journal of Fluid Mechanics. It is co-written by Bourouiba, Bush, and Eline Dehandschoewercker, a graduate student at ESPCI ParisTech, a French technical university, who previously was a visiting summer student at MIT, supported by the MIT-France program.
Smaller drops, longer distances
The researchers used high-speed imaging of coughs and sneezes, as well as laboratory simulations and mathematical modeling, to produce a new analysis of coughs and sneezes from a fluid-mechanics perspective. Their conclusions upend some prior thinking on the subject. For instance: Researchers had previously assumed that larger mucus droplets fly farther than smaller ones, because they have more momentum, classically defined as mass times velocity.
That would be true if the trajectory of each droplet were unconnected to those around it.
But close observations show this is not the case; the interactions of the droplets with the gas cloud make all the difference in their trajectories. Indeed, the cough or sneeze resembles, say, a puff emerging from a smokestack.
“If you ignored the presence of the gas cloud, your first guess would be that larger drops go farther than the smaller ones, and travel at most a couple of meters,” Bush says. “But by elucidating the dynamics of the gas cloud, we have shown that there’s a circulation within the cloud — the smaller drops can be swept around and resuspended by the eddies within a cloud, and so settle more slowly.
Basically, small drops can be carried a great distance by this gas cloud while the larger drops fall out. So you have a reversal in the dependence of range on size.”
Specifically, the study finds that droplets 100 micrometers — or millionths of a meter — in diameter travel five times farther than previously estimated, while droplets 10 micrometers in diameter travel 200 times farther.
Droplets less than 50 micrometers in size can frequently remain airborne long enough to reach ceiling ventilation units.
A cough or sneeze is a “multiphase turbulent buoyant cloud,” as the researchers term it in the paper, because the cloud mixes with surrounding air before its payload of liquid droplets falls out, evaporates into solid residues, or both.
“The cloud entrains ambient air into it and continues to grow and mix,” Bourouiba says. “But as the cloud grows, it slows down, and so is less able to suspend the droplets within it. You thus cannot model this as isolated droplets moving ballistically.”
(Cut)
Lidia Morawska, a professor at Queensland University of Technology in Brisbane, Australia, who has read the study, calls it “potentially a very important paper” that suggests people “might have to rethink how we define the airborne respiratory aerosol size range.”
However, Morawska also notes that she would still like to see follow-up studies on the topic.
The MIT researchers are now developing additional tools and studies to extend our knowledge of the subject. For instance, given air conditions in any setting, researchers can better estimate the reach of a given expelled pathogen.
“An important feature to characterize is the pathogen footprint,” Bush says. “Where does the pathogen actually go?
The answer has changed dramatically as a result of our revised physical picture.”
Bourouiba’s continuing research focuses on the fluid dynamics of fragmentation, or fluid breakup, which governs the formation of the pathogen-bearing droplets responsible for indoor transmission of respiratory and other infectious diseases. Her aim is to better understand the mechanisms underlying the epidemic patterns that occur in populations.
“We’re trying to rationalize the droplet size distribution resulting from the fluid breakup in the respiratory tract and exit of the mouth,” she says. “That requires zooming in close to see precisely how these droplets are formed and ejected.”
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Question for the thread.
Has anyone come across a full Level-4 autopsy report and lab results from such? Hard to imagine that previously occurring in Africa. New Ebola is proving we know far less about the Ebola strains than we think.