Double infections. Varieties of bacillus choleræ suis, and bacillus
suis pestis. McFadyean’s swine fever bacillus. Marseilles swine plague
bacillus.
We accept fully the duality of the Hog Cholera and Swine Plague, though
this duality has been hotly contested on both sides of the Atlantic.
Many of the best observers in Europe now support this position. These
include Selander, Bang and Jensen who are familiar with the _svinpest_
(hog cholera) of Scandinavia; Kitt, Friedberger and Fröhner who are
familiar with the _Schweineseuche_ (swine plague) of Germany; Raccugla,
Canova and others in Southern Europe; and Lignieres and others in France
who have studied the hog cholera and _pasturellose porcine_ (swine
plague).
But the conceded duality of these two diseases as they occur in typical
examples in swine, does not account for all the infectious fevers of
swine, in which these microbes or others closely allied to them may
figure. Salmon, Smith and their coadjutors describe double infections in
the same system, in which both the bacillus choleræ suis and the
bacillus pestis suis figure, and in which there result a combination of
symptoms and lesions, that together represent both of these germs. It
may be that one or other of these germs in a given outbreak, shows a
predominance in potency so that the symptoms are more characteristic of
it than of its companion; it may be that the more potent germ kills the
victim, quickly by an acute septicæmia and gross lesions that would
apply almost as well to one germ as to the other; or it may be that both
act moderately and the attack is protracted with resulting lesions in
both lungs and bowels that respectively suggest the plague and the
cholera.
Then as regards varieties in the individual germ. Th. Smith recognizes
this as a frequent condition and describes no less than seven different
types of bacillus choleræ suis which he had studied and which varied in
morphology, cultural qualities and virulence. Lignieres found that the
virulence especially of bacillus suis pestis is very easily affected by
successive passages through the bodies of small experimental animals. We
ought not to be surprised then if we find in different epizoötics, in
different countries and even in the same, bacilli which for the time at
least show characteristics different from those to which we have been
accustomed. These give us varying phases of septicæmia which however
come together in one great class. Two of these types which have been
placed on record may be here named. For others see septicæmia
hæmorrhagica of cattle and sheep.
=McFadyean’s Swine Fever Bacillus.= The characters of this microbe found
constantly by McFadyean in swine fever, approximates closely to the hog
cholera germ in morphology and motility and in its deadly action when
eaten, while it approaches toward the swine plague germ in its cultural
habits on potato, gelatine and agar, and in alkaline culture liquids,
and finally it differs from both in the absence of pathogenesis to
Guinea pigs and in its very moderate action on rabbits. The symptoms and
lesions of the _swine fever_ of Great Britain are those of the _hog
cholera_ of America rather than of swine plague.
=Marseilles Swine Plague Bacillus.= This microbe was found by Rietsch
and Jobert in a febrile epizoötic of swine at Marseilles, and was
studied by Caneva and Bunzl-Federn separately. The latter identified it
with the bacillus of ferret septicæmia, as described by Eberth and
Schimmelbusch. It was longer and thicker than the hog cholera bacillus,
twice as long as broad, actively motile, with flagella, and differed
from bacillus choleræ suis, in its polar staining, its free growth in
acid media, in acidifying and coagulating milk, and in its forming both
indol and phenol in peptonized bouillon.
In this case the source of the disease was in importations from Africa
(Fouquet), and it spread widely in Southern France for nine months. It
proved almost constantly fatal, in from four days to two or three weeks.
The symptoms were weakness especially in the hind limbs, with more or
less fever, constipation often followed by diarrhœa, an infrequent
cough, and red blotches on the skin. In chronic cases ulcers formed in
the mouth and intestines especially the cæcum and colon. Appetite was
often retained to the end. The young, under a year old, were the chief
sufferers. It made 20,000 victims in several months in the province of
Bouches-du-Rhone.