Reasonable Rascal
10-05-01, 01:18
Anthrax and Medical Preps
Do the recent events of Sept. 11 and the instance today (Oct. 4) of a case of human pulmonary anthrax I thought that a treatise of sorts on the subject was advisable.
The MSDS for anthrax exposure indicates that the average person needs to inhale between 8,000 and 50,000 spores to be considered to have taken on an infectious dose. A few spores are overcome by the body's natural defenses; thus is takes a fair number to offset this mechanism.
Host animals include humans, sheep, cattle, goats, horses and pigs. There are also reports widely substantiated of both bison and deer being likewise affected. Contrary to some reports person-to-person transmission is rare but not impossible. The likely mechanism would be coughing spores into the immediate area. [Source: Health Canada Office of Laboratory Safety]
First, prophylaxis, that is, taking medication as a precaution in case of potential exposure, is not something that should be started at the first report of actual or possible anthrax cases in humans 30 miles and farther away. There has to be a more significant indicator that that, such as sudden widespread respiratory illness other than flu, etc locally, or high level of suspicion of a possible attack locally (unexplained crop duster, tree fogger, etc).
The current recommendations for prophylaxis in the event of possible/likely exposure are a continuous course of recommended antibiotics for 60 days continuously. So unless you wish to live and these for the next few years you have to conserve what you have and use them only when appropriate. Panic reactions only lead to increased antibiotic resistance in other organisms, depletion of the supply of potentially lifesaving medications when they might be sorely and certainly needed later.
The antibiotics most recommended for treatment of a confirmed case of anthrax infection are in order of stated preference:
Penicillin G (injectable) [except for pulmonary anthrax]
Ciprofloxacin (Cipro)
Doxycycline
Tetracycline or Oxytetracycline
Penicillin (oral)
Chloramphenical
Erythromycin (least commonly recommended)
Sources of reference: Sanford Guide to Antimicrobial Therapy, 1999 Ed.; Pocket Book of Infectious Disease Therapy, 1999 Ed, by John G. Bartlett, Chief, Infectious Diseases at the Johns Hopkins School of Medicine
Dosing on these medications can be found in other articles widely available. It was vary by both weight and age when dealing with pre-adolescent children so there is no stock answer, 1-size dose fits all.
As far as those medications currently available through non-prescription sources they are:
Penicillin G
Tetracycline and Oxytetracycline
Penicillin (oral)
Erythromycin
These are available in forms usable by humans from veterinary (farm supply) and small animal supply outlets and aquarium shops variously. PenG would only be available for instance in a livestock supply outlet. Tetracycline and/or Oxytetracycline can likewise be found there in powder form or large horse pills - literally horse pills intended to be "injected" with a special pill pusher. They would need to be cut up for a human to swallow easily but they are viable as far as the medication. The powder forms have to be mixed with water and require some serious drug calculations. They are the least preferable forms of this medication for that reason but will work if no other form is available. Injectable OxyTetracycline is likewise available through these sources.
As far as isolation the type of anthrax we consider to be a war engine is the airborne version. The spores are relatively large and easily filtered. Cutaneous, or skin anthrax, infection is thought possible by the bite of insects that have fed on infected animals. Cutaneous anthrax is not the same as the pulmonary version. It is easly treated and responds readily to medications and mortality rates are very low.
The spores themselves are resistant to many disinfectants but respond well to glutaraldehyde and formalin compounds. Soaking overnight is recommended. This is for possible surface contamination only. Food cannot be decontaminated even by cooking. Bacillus anthracis is resistant to most cooking temperatures. They are highly resistant to drying, heat and direct sunlight. Sterilization requires a minimum of 121 degrees Celcius for 30 minutes. Spores remain viable in soil, skins and hides of infected animals and contaminated air and wool for decades; survival in milk - 10 years; dried on filter paper - 41 years; dried on silk threads - up to 71 years; pond water - 2 years.
Basic precautions when a possible release is suspected, or when working with potentially infected cases include N95 surgical masks with 0.1 micron filtration recommended, 1.0 micron filtration a minimum. Masks should be close fitting and changed when they become moisture laden from respiration. Adhesive tape may be necessary to affect a tight seal around certain areas of the face.
Gloves should also be worn and Tyvek or similar coveralls that can be disposed of, or isolation gowns for working with patients. Following exit from the affected area the outer barrier garments should be disposed of properly with burial in a sealed container - even a heavy duty garbage bag will work here - much preferable to burning. Hair covers such as worn in surgical rooms are also beneficial to reduce the possibility of harboring spores on the scalp despite washing.
Gas masks and supplied air respirators are extremely effective but costly, bulky and have a very limited lifespan, dependant as they are upon filters with 2-8 hours of filtration life before they become clogged. In the case of Powered Air Purifying Respirators (PAPR) battery life is also a factor.
Preparations for possible anthrax exposure then would include:
Filtration - N95 masks are extremely cost effective; gas masks are required only for battlefield level contamination
Barrier - coveralls, gowns, gloves, bonnets, shoe coverings; dependant upon the circumstances
Disinfectant - Glutaraldehyde or Formalin based solutions are the most effective. Prolonged exposure to strong bleach solution is also likely effective. Alcohol and similar disinfectants will have little to no effect.
Antibiotics - a 60 day supply per person, most likely Tetracycline or Oxytetracycline, oral Penicillin or Erythromycin. This is 60 days per possible exposure. If a 2nd potential expsore occurred while part-way through the treatment period the cycle should be extended to 60 days from that exposure to ensure safety. Barring lack of sufficient quantities though the blood levels of antibiotic may already be enough to severely shorten the lifespan of any new infection *while you are continuing on the original regimen. Protection ends within a couple of days of ceasing to take antibiotics.
Do the recent events of Sept. 11 and the instance today (Oct. 4) of a case of human pulmonary anthrax I thought that a treatise of sorts on the subject was advisable.
The MSDS for anthrax exposure indicates that the average person needs to inhale between 8,000 and 50,000 spores to be considered to have taken on an infectious dose. A few spores are overcome by the body's natural defenses; thus is takes a fair number to offset this mechanism.
Host animals include humans, sheep, cattle, goats, horses and pigs. There are also reports widely substantiated of both bison and deer being likewise affected. Contrary to some reports person-to-person transmission is rare but not impossible. The likely mechanism would be coughing spores into the immediate area. [Source: Health Canada Office of Laboratory Safety]
First, prophylaxis, that is, taking medication as a precaution in case of potential exposure, is not something that should be started at the first report of actual or possible anthrax cases in humans 30 miles and farther away. There has to be a more significant indicator that that, such as sudden widespread respiratory illness other than flu, etc locally, or high level of suspicion of a possible attack locally (unexplained crop duster, tree fogger, etc).
The current recommendations for prophylaxis in the event of possible/likely exposure are a continuous course of recommended antibiotics for 60 days continuously. So unless you wish to live and these for the next few years you have to conserve what you have and use them only when appropriate. Panic reactions only lead to increased antibiotic resistance in other organisms, depletion of the supply of potentially lifesaving medications when they might be sorely and certainly needed later.
The antibiotics most recommended for treatment of a confirmed case of anthrax infection are in order of stated preference:
Penicillin G (injectable) [except for pulmonary anthrax]
Ciprofloxacin (Cipro)
Doxycycline
Tetracycline or Oxytetracycline
Penicillin (oral)
Chloramphenical
Erythromycin (least commonly recommended)
Sources of reference: Sanford Guide to Antimicrobial Therapy, 1999 Ed.; Pocket Book of Infectious Disease Therapy, 1999 Ed, by John G. Bartlett, Chief, Infectious Diseases at the Johns Hopkins School of Medicine
Dosing on these medications can be found in other articles widely available. It was vary by both weight and age when dealing with pre-adolescent children so there is no stock answer, 1-size dose fits all.
As far as those medications currently available through non-prescription sources they are:
Penicillin G
Tetracycline and Oxytetracycline
Penicillin (oral)
Erythromycin
These are available in forms usable by humans from veterinary (farm supply) and small animal supply outlets and aquarium shops variously. PenG would only be available for instance in a livestock supply outlet. Tetracycline and/or Oxytetracycline can likewise be found there in powder form or large horse pills - literally horse pills intended to be "injected" with a special pill pusher. They would need to be cut up for a human to swallow easily but they are viable as far as the medication. The powder forms have to be mixed with water and require some serious drug calculations. They are the least preferable forms of this medication for that reason but will work if no other form is available. Injectable OxyTetracycline is likewise available through these sources.
As far as isolation the type of anthrax we consider to be a war engine is the airborne version. The spores are relatively large and easily filtered. Cutaneous, or skin anthrax, infection is thought possible by the bite of insects that have fed on infected animals. Cutaneous anthrax is not the same as the pulmonary version. It is easly treated and responds readily to medications and mortality rates are very low.
The spores themselves are resistant to many disinfectants but respond well to glutaraldehyde and formalin compounds. Soaking overnight is recommended. This is for possible surface contamination only. Food cannot be decontaminated even by cooking. Bacillus anthracis is resistant to most cooking temperatures. They are highly resistant to drying, heat and direct sunlight. Sterilization requires a minimum of 121 degrees Celcius for 30 minutes. Spores remain viable in soil, skins and hides of infected animals and contaminated air and wool for decades; survival in milk - 10 years; dried on filter paper - 41 years; dried on silk threads - up to 71 years; pond water - 2 years.
Basic precautions when a possible release is suspected, or when working with potentially infected cases include N95 surgical masks with 0.1 micron filtration recommended, 1.0 micron filtration a minimum. Masks should be close fitting and changed when they become moisture laden from respiration. Adhesive tape may be necessary to affect a tight seal around certain areas of the face.
Gloves should also be worn and Tyvek or similar coveralls that can be disposed of, or isolation gowns for working with patients. Following exit from the affected area the outer barrier garments should be disposed of properly with burial in a sealed container - even a heavy duty garbage bag will work here - much preferable to burning. Hair covers such as worn in surgical rooms are also beneficial to reduce the possibility of harboring spores on the scalp despite washing.
Gas masks and supplied air respirators are extremely effective but costly, bulky and have a very limited lifespan, dependant as they are upon filters with 2-8 hours of filtration life before they become clogged. In the case of Powered Air Purifying Respirators (PAPR) battery life is also a factor.
Preparations for possible anthrax exposure then would include:
Filtration - N95 masks are extremely cost effective; gas masks are required only for battlefield level contamination
Barrier - coveralls, gowns, gloves, bonnets, shoe coverings; dependant upon the circumstances
Disinfectant - Glutaraldehyde or Formalin based solutions are the most effective. Prolonged exposure to strong bleach solution is also likely effective. Alcohol and similar disinfectants will have little to no effect.
Antibiotics - a 60 day supply per person, most likely Tetracycline or Oxytetracycline, oral Penicillin or Erythromycin. This is 60 days per possible exposure. If a 2nd potential expsore occurred while part-way through the treatment period the cycle should be extended to 60 days from that exposure to ensure safety. Barring lack of sufficient quantities though the blood levels of antibiotic may already be enough to severely shorten the lifespan of any new infection *while you are continuing on the original regimen. Protection ends within a couple of days of ceasing to take antibiotics.