DISEASES OF THE DKJESTIVE TRACT 107 



ferti'd ilr()|)|)iii«is rarriccl on tlic t'cct of hr'Ii and animals, 

 from lu'nhousi's where the disease exists, or carried by streams 

 ar irrigation ditch water, dried and earricd by the wind as 

 dust, or carried by wild liirds. may be tlie means of introduc- 

 ing this disease among healthy birds. Even insects have ])een 

 known to carry tlie contagion. Huzzards are connnon carriers 

 of this disease. 



The germ of fowl cholera retains its power to produce dis- 

 ease for weeks, and even months, about premises where it has 

 occurred, nnless they be thoroughly disinfected. The germs 

 have been kept in test tubes, experimentally, for two years 

 and still proved to be virnlent, that is, still cai)able of pro- 

 ducing disease. It resists, for a long time. l)oth drying and 

 zero weather. 



Cholera may affect chickens, turkeys, ducks, geese, pigeons 

 and many wild birds. The period of incubation (the lime 

 elapsing from the entrance of 

 the germs into the body of the 

 l)ird until the appearance of 

 the first symptoms of the dis- 

 ease) is given as from twelve 

 to forty-eight hours. 



In our experimental work, 

 in which the virus (germ) was 

 introduced into the peritoneal 

 cavity, this period was six to 

 twelve hours; when the virus 

 was given by the mouth it re- 

 quired twenty-four to thirty-six 

 hours to produce the disease. 

 The birds died twelve to seven- 

 ty-two hours later. 



Symptoms. — The onset of this disease may be so sudden 

 that its signs pass unobserved, and finding the dead birds in 

 tlie nests or under the roosts may be the first notice that the 

 owner has of the existence of disease in his flock; or the ])irds 

 nmv have fowl cholera in a more chronic form and live for 

 six to seven days. 



In the protracted cases there is noted loss of appetite, great 

 prostration, staring feathers; the bird mo])es or sits around 

 with tail and head down, giving the so-called ''ball" appear- 

 ance, the comb is dark, tlie gait swaying, and there is trem- 

 bling, convulsions, thirst, and severe diarrhea, with passatres 

 of a greenish-yellow color. There is high fever and the bird 

 ra])idly becomes emaciated. 



The percentage of loss in the flock, if not treated, is very 



Fi< 



-14. 



FROM 



Case 



Blood Smear 

 OF Cholera. 



Sliowing red blood cells, clirom- 

 bocytes, mononuclear neutropliiles and 

 many of the po!?r staining geruis 

 n*.acilliis avisepticu=) of the dis^eas'^. 



