52 
North Carolina Experiment Station 
Strictly speaking, avian typhoid should be classified as an infectious dis¬ 
ease, which, according to Kolmer (19), is a disease which is the result of indi¬ 
rect transmission. 
Such a type of disease, according to the same authority, passes through the 
following stages: 
1. The period of incubation, which begins at the time of infection, and ends 
with the development of the earliest symptoms, during which time the invad¬ 
ing parasites are multiplying in the tissues of the host. During this stage 
no symptoms, or only those of a purely local nature, are present. The period 
varies considerable in different infections, and to a lesser degree in different 
individuals having the same infection. 
In artificial infection experiments with avian typhoid, 35 out of 39 adult 
birds contracting the disease showed clinical symptoms in from 3 to 6 days; 
three of the remaining ones did not develop symptoms until the 7th day, and 
the fourth one did not show symptoms of the disease until the twenty-first 
day. The last bird possessed high natural resistance to avian typhoid, as 
30 days elapsed before the bird finally succumbed. 
2. The period of prodromal symptoms, characterized by systematic disturb¬ 
ances of a relatively mild type, due to the diffusion of bacteria and their 
products into the general circulation, and their wide-spread effect upon the 
body cells in general. 
Sufficient data was not accumulated in these artificial infections to arrirve 
at a definite conclusion as to the stage of the disease when a bacteremia 
begins and ends. Successful isolations of E. sanguinaria from the blood cur¬ 
rent were made in two instances, one 3 days after infection, and the other on 
the 6th day. All birds infected were tested daily for a bacteremia, but nega¬ 
tive results were obtained except in the above mentioned cases. There is 
probably an overlapping in these two periods in infection with avian typhoid, 
varying undoubtedly, with the severity of infection and the resistance of the 
bird. Through the latter part of the period of incubation, until the period of 
fastigium or high fever, there is a material derangement of the bowel, the 
dejecta being watery in consistency, and sulphurus in color, the coloration 
being due to bilirubin and biliverdin. 
3. The period of Fastigium or high fever, in which the disease is at its 
height. 
In avian typhoid, this period finds its inception and duration in the resist¬ 
ance of the individual bird, and the severity of infection. In birds infected 
artificially, the third period could be designated as commencing from the 
third to the sixth day, the birds succembing, as a rule, in less than ten days. 
As indicated by Kolmer, the period of Fastigium, during which the birds 
which succumb to the disease usually die, is one in which the host is over¬ 
whelmed with the toxic split portion of the newly formed bacterial protein. 
The fever is the resultant of disturbance in the circulatory, respiratory, and 
heat regulating mechanism, and in general metabolism. 
4. The period of decline, during which the patient is gradually overcoming 
the infection, and amelioration of the symptoms takes place. 
5. The period of Convalescence, in which the host gradually overcomes the 
effects of the disease and returns to health. 
In periods 4 and 5 in avian typhoid, the transformation from period 3 is 
relatively abrupt, birds seemingly overcoming the effects of the disease over 
night, a return to normal condition ensuing. 
Salmon in his original experiments on avian cholera, arrived at the con¬ 
clusion that 18 out of 100 birds possessed natural immunity to the disease. 
