_Definition._ Causes. Bacillus septicæmiæ gangrenosa, anærobic, rarely
in living blood. Source of germ in soils. Pathogenic to man and
domestic animals except cattle. First attack immunizes. Infects deep
wound, exudates, dropsical and gangrenous parts, womb, intestine,
debilitated parts, large dose intravenously. Lesions and symptoms:
excess of exudate, boggy swelling, watery discharge, fœtid gas
bubbles, œdema of lungs and bowels. Complex infection. Minimum
dose—abscess. Diagnosis: from black quarter and anthrax. Treatment:
free incisions, hydrogen peroxide. Prevention: disinfection of skin
and wounds. Immunity.
_Definition._ An acute bacteridian disease of domestic and wild mammals,
and of man, manifested by doughy, painful and often crepitating swelling
in the vicinity of the affected part, and proving fatal in many cases in
twenty-four to forty-eight hours.
_Cause._ The essential cause is the bacillus of malignant œdema, the
septic vibrio of Pasteur, bacillus septicus gangrenæ of Arloing, the
bacillus of septicæmia gangrenosa of others.
_Morphology._ This is a staff-shaped microbe 3–4 μ. long by 1 μ. broad,
often united in chains of three or more to form long flexuous filaments.
They are furnished with numerous flagella by which they are rendered
very actively motile. The movements are tardy or simply flexuous in the
filaments. Spores form in the isolated bacilli (not in the filaments) in
suitable culture media and at a temperature of from 20° to 38° C. They
occupy a place near the centre of the bacilli, not the ends as in the
bacillus of emphysematous anthrax. The bacilli are anærobic and die
quickly in air, but the spores are unaffected by oxygen. The spores are
similarly resistant to most disinfectants. They will grow readily in
ordinary culture media if oxygen is excluded, for example under an
atmosphere of hydrogen, nitrogen or carbon dioxide, and liquefy
gelatine. Even the oxygen present in the circulating blood is highly
inimical to them, so that they are rarely found in the blood during
life, but rapidly invade both it and the tissues after death, and the
suspension of respiration. In peptonised and glucosed gelatine the
colonies are characterized as globules of liquefaction usually combined
with gas. The germ is widely distributed in soils in general and not
confined to limited areas like the bacilli of anthrax and black quarter.
_Animals susceptible._ The bacillus attacks man, horse, ass, goat,
sheep, pig, mouse, Guinea pig, rabbit, white rat, cat, dog, chicken,
pigeon, and duck. The mature ox is immune, but calves suffer. Dogs are
often immune having already suffered from the disease. A first attack
gives immunity from a second.
_Infection Channels._ Inoculation on an abrasion of the skin or surface
sore is not usually infecting, the oxygen of the air destroying the
germ. If, however, it is inserted deeply in the connective tissue,
subcutem, it grows readily in a susceptible animal. Hence the danger of
infection in deep wounds the recesses of which are not exposed to the
air, and in such it becomes a most redoubtable surgical complication. If
such wounds are the seat of active inflammation, with abundant exudate
and more or less exclusion of the air-bearing blood, and in cases of
blood stasis the field is specially inviting to the bacillus.
The debility of the injured tissue is a further invitation to the
attack. Chauveau injected 4 to 5cc. of virulent liquid of malignant
œdema into the veins of a ram and then practised bistournage, with the
result that an invasion of malignant œdema of the scrotum and tunica
vaginalis followed immediately. Pure cultures may be harmless, whilst an
admixture of proteus vulgaris or micrococcus prodigiosus renders them
most deadly (Penzo). Granulating wounds are even less favorable to
invasion than simple abrasions. In these the bacillus cannot enter at
once into the lymph channels and is exposed to destruction by the
combined influence of the air and leucocytes.
Wounds in dropsical or gangrenous parts are equally favorable, to the
development of the bacillus. Under such conditions the tissues are
wanting in oxygen and resemble the condition of the entire body after
death, when the bacillus of malignant œdema quickly penetrates its whole
substance. Petri has traced the infection through the genital passages
of newly delivered rabbits, producing a fatal metro-peritonitis and
cutaneous œdema. A similar invasion may take place in other susceptible
parturient animals. Lustig in a certain number of cases satisfied
himself that he had traced the invasion through the intestine of the
living horse. Invasion by the lungs, even by spores, is usually rendered
impossible by reason of the presence of the inspired air.
A large dose of the virus is most likely to effect a successful
invasion, since the toxins tend to debilitate and lower the defensive
powers of the tissues and leucocytes. The effect of the toxins is shown
under injections into the arteries, veins or trachea. A certain amount
of hyperthermia follows, but there is rarely any colonization and
reproduction of the bacillus in the connective tissue. In dogs and
rabbits large doses given in this way induce short inspiration and
broken or double expirations. In fatal doses death is preceded by
extreme dyspnœa and convulsions. (Rodet and Courmont).
_Lesions and Symptoms._ The tissues where invasion occurs, become the
seat of an abundant œdematous exudation, which feels boggy and painful
and may even crepitate when pressed or manipulated. In case of an open
wound, there is a profuse liquid discharge of a yellowish watery or
serous aspect, and bubbles of gas or froth having a somewhat fœtid odor.
The center of the swelling may become soft and flaccid while the
peripheral parts where the disease is advancing are tense and resistant.
In fatal cases the mucosæ of the small intestine and lungs are usually
the seats of œdema in which the bacillus is found. The bacilli may also
be found in the liver. It is noticeable that gross lesions of the spleen
and kidneys are usually absent, in marked contrast with anthrax. The
microbes found in the tissues may be in the form of bacilli, micrococci
(spores, or m. prodigiosus), and sometimes filaments.
Inoculation with a minimum dose usually results in local abscess only.
_Diagnosis._ From _emphysematous anthrax_, with which malignant œdema is
most likely to be confounded, it is to be distinguished by its
appearance anywhere outside the black quarter areas, by the immunity of
cattle which are so obnoxious to emphysematous anthrax, by the
susceptibility of man, who does not contract black quarter, by the
formation of the spore near the middle of the bacillus in place of at
one end, by its resistance to the action of ordinary disinfectants, and
by the greater tendency to form filaments.
From _anthrax_ it is differentiated by its appearance outside the
anthrax localities, by the absence of the bacillus from the blood and
from the surface layers of the skin, by the normal size of the spleen,
and by the active motility of the bacillus. It cannot be cultivated like
anthrax in the free air or on the surface of culture media, and unlike
anthrax bacillus, its cultures produce bubbles or gas.
_Treatment._ This is essentially surgical and consists in free incisions
to admit air freely to all parts of the œdematous tissue, perfect
drainage and a liberal use of peroxide of hydrogen. Other disinfectants
may be employed but are much less promising. The free disinfection of
the adjacent skin is an important element in treatment.
_Prevention._ This consists essentially in the thorough disinfection of
all accidental and surgical wounds, the careful cleansing and antisepsis
of the skin before an operation, the exclusion of earth, manure, or
water from driven wells or fountains, from all wounds, and above all the
exclusion of proteus vulgaris, and micrococcus prodigiosus.
_Immunity_ may be secured by a first, non-fatal attack of the disease.