[EMED-L] Airborne anthrax protection... (fwd)

[measl at mfn.org]

interesting trivia for the biowar inclined :-)

---------- Forwarded message ----------
Date: Thu, 25 Oct 2001 10:37:28 -0700
From: Tim Sturgill <kasei at POBOX.COM>
Reply-To: EMED-L -- a list for emergency medicine practitioners.
    <EMED-L at ITSSRV1.UCSF.EDU>
To: EMED-L at ITSSRV1.UCSF.EDU
Subject: Re: [EMED-L] Airborne anthrax protection...

>From JAMA. 1999;281:1735-1745. "Anthrax as a Biological Weapon: Medical
and Public Health Management"

@ http://jama.ama-assn.org/issues/v281n18/ffull/jst80027.html

"The nonflagellated vegetative cell is large (1-8 microns in length,
1-1.5 microns in breadth). Spore size is approximately 1 micron."

The germinated B anthracis is _larger_ than the _singular_ spore
(dormant) state (the gram positive rod). The spores are being milled to
the "spherical" and "singular" spore size, around 1 micron. The spores
unmilled may clump greatly (as reported for the Boca Raton letter) as
part of the process that was used to cause sporulation of the growing B
anthracis stock. Also they clump because of electrostatic charge (which
is now being reported to have been defeated).

My question is how do the TB and HEPA masks function with 1 micron size
particles that are  electrostatically neutral. I would assume that all
these masks were designed from the premise that small particles will
always have a electrostatic charges--since only artificially made
particles (requiring great technical skill) can be made
electrostatically neutral.

Is the filter a physical barrier at 0.3 microns? Or is this a physical +
electrostatic barrier at 0.3 microns (which means that the physical
component may be much greater)?

regards/t

_/_/_/_/ _/_/_/_/ _/_/_/_/ _/_/_/_/ _/_/_/_/
Tim Sturgill MD FACEP FAAEM
logres at pobox.com
_/_/_/_/ _/_/_/_/ _/_/_/_/ _/_/_/_/ _/_/_/_/

> -----Original Message-----
> From: EMED-L -- a list for emergency medicine practitioners.
> [mailto:EMED-L at ITSSRV1.UCSF.EDU] On Behalf Of James Li, M.D.
> Sent: October 25, 2001 04:26
> To: EMED-L at ITSSRV1.UCSF.EDU
> Subject: [EMED-L] Airborne anthrax protection...
>
>
> Anthrax spores are large, the smallest dimension around 0.7 microns
> (diameter) by 3.0 microns (length, but often much longer).
> "Spores may be larger than the diameter of the bacillus, but
> usually are not." [1] The Washington Post article refers to a
> diameter of 1.5 to 3.0 microns wide, but I think this may
> have been a misquote (and length instead).
>
> Thus, a TB mask should be sufficient, as Dr. Siegelson
> states. Given the article from the Washington Post, and the
> postal cases that weren't supposed to happen (aerosolized
> particles from "low risk" letter sources), it's probably
> important to wear these in the ED in cases of suspected
> exposure, until decontamination is clearly confirmed. We use
> a standard N95 particulate mask at work (which is available
> at any hardware store for sanding and painting work). In
> addition, I would suggest using a HEPA (high efficiency
> particulate arrestance) filter, which actively removes
> particles at the sub ~0.3 micron level from ambient air, in
> areas that might become contaminated. These also are readily
> available, for under $100. I've been using a nice quiet desk
> top HEPA filter for regular dust in my own house for years,
> and got it from Wal-Mart for about $70.
>
> James Li, M.D.
> Division of Emergency Medicine
> Mount Auburn Hospital
> Harvard Medical School
>
>
http://www.remotemedicine.org

REF
[1] Medical Microbiology, Sherris JC, ed. pp. 319.

----ORIGINAL MESSAGE-----
I think that the TB mask is sufficient protective equipment from
airborne spores, although there is no indication that it would be needed
while treating a patient.  Also, there is no reason to decontaminate the
patient with soap and water.  If he is worried, remove his clothes and
send him
home.  He can take a shower there if he likes.   If you wash the
patient,
the water can go down the drain.

Henry Siegelson, MD, FACEP

To unsubscribe, send the command  "SIGNOFF EMED-L" to
LISTSERV at ITSSRV1.UCSF.EDU

To unsubscribe, send the command  "SIGNOFF EMED-L" to LISTSERV at ITSSRV1.UCSF.EDU