In pigeons: Ærobic, non-motile bacillus, in lesions, membrane and
internal organs, pathogenesis, in chickens pathogenesis differs, also
in man, parts attacked, exudate, other symptoms, mortality early and
late in outbreak, American form, pathogenesis to rabbits and
Guinea-pigs. Prevention: Avoidance of infection, quarantine of birds,
separation of sick, disinfection, accidental bearers of infection,
pigeons, buzzards, carrion crows, dogs, men, cleanliness. Treatment:
Locally antiseptics, phenol, boric acid, generally, phenol.
This has been especially seen in pigeons in which it has been studied by
Löffler, Cornil and Megnin, and Babes and Puscarin. Löffler found an
ærobic, non-motile, non-liquefying bacillus in the false membranes,
inflamed tissues, liver, lungs and blood, even in the leucocytes. It
formed irregular masses, and grew in nutrient gelatine, blood serum and
potato. It proved pathogenic to pigeons, linnets, rabbits and mice, but
not to hens, Guinea-pigs, rats or dogs. Chickens, however, suffer from
an acute diphtheritic affection caused by a nearly allied bacillus, and
it remains to be seen whether the varying pathogenesis may not be due to
the habit of long continued growth in a particular genus and an acquired
unfitness for growing in the other. The pathogenesis is also different
from the bacillus of diphtheria of man, and the two diseases are not
usually inter-communicable, in spite of the fact that in rare instances
infection has appeared to have taken place from man to birds.
In pigeons and fowls the upper parts of the air passages and digestive
tract are mainly involved, the tongue, fauces, corners of the mouth,
nares, larynx, and conjunctiva. The bowels suffer less frequently and
mostly concurrently with the mouth, nose and throat. The mucosa is
deeply congested and in part covered by a yellowish exudate which may
accumulate in masses, and dry into a firm substance. The disease affects
particularly high bred birds, kept in close warm houses, and is often
imported by prize animals returned from a show. There may be dullness,
listlessness, sunken head, trailing wings and tail, erect plumage,
diarrhœa, and, if the nose and throat are affected, a modification of
the voice as in roup. Death may occur from asphyxia from the second to
the fourth day near the beginning of an outbreak or the illness may last
twenty days, after the more susceptible birds have been killed off.
In investigating a series of outbreaks of roup in chickens in America,
Dr. V. A. Moore found a non-motile bacillus allied to the colon bacillus
which proved much more deadly to rabbits and guinea pigs than to
chickens, and which was not found in the blood nor internal organs but
only in the local lesions where inoculated. The disease tended to assume
a chronic type in place of the acute form as seen in Europe. Three
inoculated chickens escaped the disease altogether. It would appear
therefore that we have here a disease distinct from that described by
Lœffler, or that there was an absence of some unknown predisposing or
contributing conditions that were present in the European outbreaks. In
both diseases however infection is an undoubted factor and similar
measures of prevention and even of treatment may be followed.
_Prevention._ The first consideration is the seclusion of flocks from
outside animals in affected localities. Newly purchased birds or those
returning from a poultry show should be placed in strict quarantine for
a few weeks until the absence of infection shall have been demonstrated.
Different flocks should not be allowed to mingle, nor the members of a
healthy flock to wander where the manure of another flock has been laid.
Birds having diarrhœa, or any discharge from eyes, nose or beak, or any
false membrane on such parts should be excluded from the flock, and the
house and yard disinfected. It should not be forgotten that rabbits,
guinea pigs and mice may be bearers of the infection, and that it may be
introduced on the feet of dogs or their masters. Pigeons, buzzards, and
carrion crows are especially dangerous as possible bearers of the
infection. Cleanliness as regards food and water, buildings and yards is
of vital importance.
_Treatment._ The sick birds should be strictly secluded and handled by a
special attendant. When the lesions appear on visible mucosæ they should
be painted several times a day with a 5 per cent. solution of phenol, or
a saturated solution of boric acid, or salicylic acid, potassium
permanganate, iodine, or some other germicide may be used. For the bowel
affection one or two drops phenol in water may be given daily, and the
drinking water should be slightly charged with the same. Cleanliness,
pure air, warmth, dryness and sloppy food are all important.