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I still don't understand the reasoning. Does anyone else? Is it the cost of the equipment, or is it just too cumbersome in a hospital environment? I think the security workers had their own air supply and may have been at or close to BSL-4 protection in the video from the recent airliner scare.
http://www.usamriid.army.mil/biosafety/
Yet CDC's recommendations for HCW's are much less stringent.
http://www.cdc.gov/vhf/ebola/hcp/inf...endations.html
Why? Researchers warned in 1995 that modern hospital workers might have increased risk, rather than less risk than HCW's in more primitive facilities in ebola endemic areas.
http://www.ncbi.nlm.nih.gov/pmc/arti...00004-0007.pdf
And even in that warning, I still don't see why BSL-4 standards were not recommended. Also, I'm not sure why they ruled out simultaneous ocular infection in the monkeys since I don't see that their eyes were protected in the head exposure chambers.
It would be comforting to know that this experiment that involved considerable animal suffering had resulted in protection of modern hospital workers, but I don't see that result so far.
http://www.usamriid.army.mil/biosafety/
— Biological Safety at USAMRIID —
Established in 1969, USAMRIID has decades of experience operating containment laboratories and has provided extensive training and consultation to other agencies setting up their own facilities. We consider safety—of our employees, our neighbors, and the surrounding community—our number one priority.
There are four levels of biological containment, ranging from Biosafety Level (BSL)-1, the lowest, to BSL-4, the highest. BSL-1 would be comparable to an open bench laboratory found in a school classroom—no special precautions would be needed. At BSL-2, USAMRIID employees wear laboratory coats and observe other basic precautions. For BSL-3 work, we require our personnel to change into scrub suits before entering the laboratory and take a complete shower before exiting. Other personal protective equipment may be required as well, depending on the tasks to be performed. BSL-4 is the highest level of containment, and employees wear positive-pressure suits commonly called "space suits" and breathe filtered air as they work.
Established in 1969, USAMRIID has decades of experience operating containment laboratories and has provided extensive training and consultation to other agencies setting up their own facilities. We consider safety—of our employees, our neighbors, and the surrounding community—our number one priority.
There are four levels of biological containment, ranging from Biosafety Level (BSL)-1, the lowest, to BSL-4, the highest. BSL-1 would be comparable to an open bench laboratory found in a school classroom—no special precautions would be needed. At BSL-2, USAMRIID employees wear laboratory coats and observe other basic precautions. For BSL-3 work, we require our personnel to change into scrub suits before entering the laboratory and take a complete shower before exiting. Other personal protective equipment may be required as well, depending on the tasks to be performed. BSL-4 is the highest level of containment, and employees wear positive-pressure suits commonly called "space suits" and breathe filtered air as they work.
http://www.cdc.gov/vhf/ebola/hcp/inf...endations.html
Why? Researchers warned in 1995 that modern hospital workers might have increased risk, rather than less risk than HCW's in more primitive facilities in ebola endemic areas.
http://www.ncbi.nlm.nih.gov/pmc/arti...00004-0007.pdf
Int J Exp Pathol. Aug 1995; 76(4): 227–236.
PMCID: PMC1997182
Lethal experimental infections of rhesus monkeys by aerosolized Ebola virus.
E. Johnson, N. Jaax, J. White, and P. Jahrling
...
Our experiments were conducted at
240C and < 40% RH, conditions which are known to
favour the aerosol stability of at least two other African
haemorrhagic fever viruses, Rift Valley fever and Lassa
(Stephenson et a/. 1984; Anderson et a/. 1991). If the
same holds true for filoviruses, aerosol transmission is
a greater threat in modern hospital or laboratory
settings than it is in the natural climatic ranges of
viruses.
...
Regardless, we have shown that Ebola virus (Zaire
strain) can be transmitted by aerosol in an experimental
primate model. In light of the pathogenicity of human
filovirus infections, health care personnel at risk of
exposure should use precautions to minimize the risk
of aerosol exposure while managing acutely ill haemorrhagic
fever cases of unknown or filoviral aetiology.
The risk can be markedly reduced by adhering to sound
and practical infectious disease management procedures.
This requires curtailing aerosol generating procedures;
using protective clothing, including gloves and
masks; adequately decontaminating potentially infectious
material; and conducting virus diagnostic procedures
in regional containment facilities capable of safely
handling highly hazardous infectious agents (Comperts
et a/. 1978; CDC 1988).
PMCID: PMC1997182
Lethal experimental infections of rhesus monkeys by aerosolized Ebola virus.
E. Johnson, N. Jaax, J. White, and P. Jahrling
...
Our experiments were conducted at
240C and < 40% RH, conditions which are known to
favour the aerosol stability of at least two other African
haemorrhagic fever viruses, Rift Valley fever and Lassa
(Stephenson et a/. 1984; Anderson et a/. 1991). If the
same holds true for filoviruses, aerosol transmission is
a greater threat in modern hospital or laboratory
settings than it is in the natural climatic ranges of
viruses.
...
Regardless, we have shown that Ebola virus (Zaire
strain) can be transmitted by aerosol in an experimental
primate model. In light of the pathogenicity of human
filovirus infections, health care personnel at risk of
exposure should use precautions to minimize the risk
of aerosol exposure while managing acutely ill haemorrhagic
fever cases of unknown or filoviral aetiology.
The risk can be markedly reduced by adhering to sound
and practical infectious disease management procedures.
This requires curtailing aerosol generating procedures;
using protective clothing, including gloves and
masks; adequately decontaminating potentially infectious
material; and conducting virus diagnostic procedures
in regional containment facilities capable of safely
handling highly hazardous infectious agents (Comperts
et a/. 1978; CDC 1988).
It would be comforting to know that this experiment that involved considerable animal suffering had resulted in protection of modern hospital workers, but I don't see that result so far.
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