POULTRY DISEASES 
15 
NON-PARASITIC DISEASES 
FOWL CHOLERA, OR CHICKEN CHOLERA 
CAUSE.—Chicken cholera is caused by a germ (B. avisepticus) and is a 
blood disease (septicaemia). The germ is rather short and plump and, with 
aqueous fuchsin, stains at the poles or ends deeper than at the middle, hence 
it is called a polar staining bacillus. Figure 18 shows the germ magnified 
1,000 times. This drawing was made from the blood smear from an out¬ 
break among turkeys and chickens. The cells are varieties of blood cells. 
One of these, a white blood cell (a phagocyte) has apparently taken up one 
of the germs. See figure 18. 
Figure 18.—Blood smear from a case of fowl cholera, magnified 1,000 times. 
The germs, B. avisepticus, are scattered among the various blood cells. One white 
blood cell (polymorphonuclear neutropliile) has apparently taken up one of the 
germs. 
MODE OF SPREAD.—Show birds often bring home the disease, or in¬ 
fected birds are introduced into the flock. Sometimes it is spread by eggs 
from an infected flock, by chicks recently hatched, or by infected droppings 
from infected hen houses tracked on the feet of men and animals, carried 
by streams or irrigation water, or dried and carried by dust or by wild birds. 
The disease has been studied in this laboratory from one outbreak among 
turkeys and chickens, another among chickens, and still another among ducks. 
It may also infect pigeons, geese and wild birds. Buzzards are common car¬ 
riers of the disease and insects have been known to carry the contagion. The 
germ retains its power to produce disease for weeks and even months. It 
resists, for a long time, both drying and severe cold weather. The period of 
incubation, that is from the time the germ enters the body until the disease 
symptoms appear, is given as from 12 to 4 8 hours. In our experimental work 
in which the virus (germs) was introduced into the peritoneal cavity, the 
period of incubation was 6 to 12 hours, and by the mouth 24 to 3 6 hours. The 
birds died 12 to 72 hours later. 
SYMPTOMS.—The signs of the disease may be of so short duration that 
they will pass unobserved and the birds be found dead in the nests or under 
the roosts, or the birds may live 6 or 7 days. In these latter cases the bird 
mopes or sits around with tail and head down giving the so-called “ball” 
appearance. There is loss of appetite, great prostration, stairy feathers, 
dark comb, swaying gait, trembling, convulsions, thirst and intense diarrhoea. 
There is a high fever. The bird rapidly becomes emaciated. The disease 
spreads rapidly in the flock, and the percent of loss, if not treated, is very 
great. Pure breeds are more susceptible than scrubs. In the outbreak 
studied among ducks, the disease progressed very slowly, only from one to 
five or six dying in the course of a week. There were about 500 in the flock. 
AUTOPSY.—Upon opening the abdominal cavity, one will first note the 
greatly enlarged liver, very dark in color, inflamed and easily torn, showing 
congestion and cloudy swelling. Sometimes the liver weighs 120 grams, or 
three times its normal weight. The intestines are congested and contain 
