Botulinum toxins are the
produce of the Clostridium Botulinum species, a gram positive bacillus
(rod), anaerobic, spore forming, which is found everywhere in the environment.
The name Botulinum derives from the Latin botulus, which means sausage.
Botulism, the disease caused by the toxins, it is originally known in fact
from consumption of contaminated, not enough deeply cooked sausages. The
contamination of sausages would happen because of the ubiquitous presence
of the organism and lack of elementary principle of hygiene. In other words
the maker of the sausage would contaminate just by not washing their hands,
or working on the minced meat on or over contaminated surfaces. The spore
would germinate in anaerobic environment such as within the sausage and
in turn the organism would produce the toxins. This has been also a frequent
happening at the origin of tinned food industry, when gas would form within
a tin this was an indication of the germination of the organism. Toxins
do not have any particular flavor or odor, and germination of the bacillus
and gas formation is also not smelling, opposite to many anaerobes. Some
of the toxins digest food giving to it a spoiled appearance, some do not
leaving the food unchanged. Some other Clostridium species (Clostridium
butyricum -of the butter- and Clostridium barati) have been known to produce
toxins.
Botulinum toxins, there
are seven of them, are neurotoxins, they work at the neuromuscular junction
and cause generalised paralysis. The clinical picture it is a paralysis
beginning in the muscles of the head and then progressing in succession
to the neck, upper arms, body trunk and legs. Death supervenes by stop
breathing and suffocation.
Toxins are deactivated by
home cooking at 100 degrees for ten minutes. However is well know that
a variety of food boiled for ten minutes do not reach in the inner part
that temperature. The boiling for ten minutes at 100 degrees is therefore
a notion valid for fully exposed toxins. It toxins are deeply endowed in
a large sausage, as it is possible, the roasting of the sausage, or even
its boiling for ten minutes is not to be expected to deactivate the toxins.
Spores are killed at 120 degrees for twenty minutes (steam sterilization
or pressure cooking) and this procedure is deactivating toxins as well.
Toxins are of course resistant to gastric content.
Clinical botulism is traditionally
described in four types,
-the first is food borne
poisoning, caused by the presence of toxins in food. However the presence
of toxin does not mean toxins are introduced in the food, but rather that
there were spore and anaerobic condition in the food, spore would germinate
because of the anaerobic conditions, and toxin would be produced within
the food
-second is wound botulism,
the bacillus would contaminate a wound and produce toxin
-infant botulism caused
by ingestion of spore and germination in the intestine and toxin production
-undetermined, including
some cases of adult with the same mechanism as for infant type.
How a botulinum attack could
take place is difficult to say, toxins are relatively heat resistant but
no information are available on activity in relation to dry condition.
It is not known if they were planned to be used in the alimentary chain
or just spread as such in form of aerosol. A possibility would be spreading
of botulinum toxins in the water. However these toxins are rapidly inactivated
by standard potable water treatment such as chlorination and aeration.
It is conceivable though that toxins could remain active for several days
in untreated water. Opposite to other agents there are no reports of industrial
accidents or terrorist attacks nor of epidemic of paralysis which could
be attributed to accidental or not mass spreading of the toxins. All industrial
accidents, the last reported caused by toxins present in the thick cream
industrially processed, have resulted in one or two death.
The incubation Period
Incubation is the time between
assumption of the toxin and the beginning of symptoms. The rapidity of
onset and severity of symptoms depend on the rate and amount of toxin absorption.
Food borne botulism may give symptoms as early as two hours and as late
as 8 (eight) days after ingestion of toxins. Typically cases presents 12
to 72 hours after the implicated meal. In large food borne outbreak, new
cases presented during the ensuing 3 days at a fairly even rate before
decreasing.
The time to onset of inhalation
botulism cannot be stated with certainty. In experimental animals, monkeys
showed signs of botulism 12 to 80 (eighty) hours after aerosol exposure
four to seven time the monkey median lethal dose. The three known human
cases of inhalation botulism had onset of symptoms approximately 72 hours
after exposure to an unknown but probably small amount of aerosolized toxin
(J.A.M.A.) Like in untreated water, is conceivable that toxin could remain
active in aerosol for at least a few days.
One can therefore presume
two things
Note on the Sodium Hypochlorite (bleach) solutions:
While concentration of 0,025
of bleach in water (5 cc of bleach per liter of water) are the one used
for infected wound irrigation because they have bactericidal property and
no tissue toxicity, (J Burn Care Rehabil 1991 Sep-Oct, 12(5) 420-4), this
concentration is irritating eyes and mucosae. A more diluted one should
be used , 1 to 2 cc per liter (0,005 to 0,01), when the purpose is purely
decontamination of eyes from both mustard and nerve agents. Conversely
a more concentrated solution (10 cc of bleach per liter of water ) can
be used in recently contaminated intact or superficially burned skin, followed
by water rinsing. These dilution are referred to normal commercial preparation
of bleach, which have a sodium hypochlorite concentration of around 5%.
More diluted preparation should be used accordingly. If the commercial
preparation is said to be 2,5% the given amount of bleach should be doubled.
More concentrated commercial preparation should conversely diluted more.
When in doubt the prepared concentration should be tested in the mouth,
the 0,05 concentration is definitely felt strongly in the oral mucosa,
and is revolting to drink, while the 0,005 should still give a flavor-taste
of diluted chlorine as for instance in a swimming pool water.
CDC gives these approximate
relation between sodium hypochlorite concentration and ppm (part per millions):
500 ppm correspond to a dilution 1:100 of household bleach, equal to 10
cc of 5% bleach in one liter of water. 5000 ppm is 100 cc of 5% bleach
per liter of water. These concentrations are relevant for sterilization
or disinfection purposes (Clinical Microbiology Reviews Oct 1997, p.597-610).
By contrast drinkable water
has a chlorine concentration of 0,5 ppm (dilution of household bleach of
0,01 cc per liter of water). Depending on the bacterial or viral contamination
of water to be chlorinated, concentration of 0,1 ppm to 0,5 ppm, or up
to 2,0 ppm of free chlorine are reached. Some time this is expressed in
weight by volume since water chlorination is done with solid chlorine releasing
substances. So the Sphere project indications for drinkable water at the
tap are of 0,2 mg to 0,5 mg of residual free chlorine per liter of water.
One should remember that there are substantially three methods of water
potabilization (Chlorination). One is the addition of Calcium hypochlorite
solution, which will then be given as a final concentration of weight by
volume. A slight confusion may arise from the fact that Calcium hypochlorite,
a powder, is said to give around 70% of free chlorine when dissolved in
water. It is then better to refer to the actual residual free chlorine
(residual refer to the chlorine that has not interacted with organic material)
when talking of final free chlorine concentration. At any rate talking
abstractly about units of measurement, 1 (one) mg per liter (1 mg/L) is
the same than 1 (one) part per million (ppm). This is because one milligram
is = one thousandth of a gram, while a liter (of distilled water) is =
to thousand grams. So 1000 x 1000 = 1,000,000. Calcium hypochlorite is
the most commonly used. A second one is chlorine gas, which is becoming
more and more obsolete. A third one is Sodium hypochlorite, which comes
in liquid form (bleach) because the method to produce it was originally
from salted water electrolysis (H2O + NaCl------ NaOCl). For practical
purpose only Calcium hypochlorite (powder or tablets), or Sodium hypochlorite
solution (bleach) are used in emergency situation.