Text book of veterinary medicine, Volume 4 (of 5)Law, James
Science
Text book of veterinary medicine, Volume 4 (of 5)
Law, James
Veterinary medicine
Even the bacilli are comparatively resistant to ordinary disinfectants,
and, as spores form in the body very rapidly after death, and in
virulent products, it is always best to assume their presence. In a
moist medium Cl. 44.7% destroyed the spores in 3 hours: HCl (1:1100) in
2 hours: HgCl (1:1000) in a few minutes: HgI_{2} (1:20000) in 2 hours:
Malachite green (1:40,000) in 2 hours: Methyl violet (1:5000) in 2
hours: Aseptol (1:10) in 10 minutes: Carbolic acid (4:100) with HCl
(2:100) in 1 hour.
_Action of septic ferments on the bacillus anthracis._ Rapid
putrefaction in the anthrax carcass which has not been opened tends to
speedy granular degeneration and death of the bacillus anthracis, so
that the blood and tissues may be no longer infecting after six days in
summer. In such cases the irrespirable gaseous products of decomposition
drive out the oxygen without which the bacillus cannot live. If,
however, spores have already formed or if air is freely admitted the
infection survives in spite of decomposition. The search for the bacilli
may thus be fruitless as soon as decomposition is well advanced and the
material can only be virulent through any spores that may have formed.
Eventration serves to retard sepsis and admit air to form spores, and
salting operates in a similar manner.
The infected hides, the nasal, buccal, kidney and bowel discharges, and
spilt blood and exudates mingling freely with the air tend to form
spores and to preserve and propagate the contagion. On the contrary
prompt and deep burial, without opening the carcass and before spores
can have formed will usually ensure its destruction. The main danger in
such cases comes from infecting matter (adherent to the surface of the
body) which sporulates easily. This serves to explain the great danger
of working in anthrax hides, leather, horn, wool, hairs and bristles. It
also explains sporulation and preservation of infection when the
virulent excretions, blood, etc., mix with the surface layers of soil.
This may happen at a greater depth (3 or 4 feet) in a very porous soil
and where the temperature is sufficiently elevated (above 14° C.) It may
even occur in water. The dried spores are mostly carried in dust, hay,
fodder, and running streams.
Since 1892 anthrax has prevailed along the banks of the Delaware river
for a distance of 40 miles in N. J. and Del., destroying from 70 to 80
per cent of the farm stock. The great morocco industry on this river
draws infected hides from India, China, Russia, Africa and South
America, and the spores are carried and distributed by the tides.
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