CHAPTER IV 
FOWL CHOLERA 
Synonyms. Chicken cholera, pasteurellosis avium, cholera gal- 
linarum, hemorrhagic septicemia of fowls; Hiihnercholera, (Ger- 
man) ; choléra des poules, (French). 
Characterization. Fowl cholera is an acute contagious septi- 
cemic disease affecting domesticated birds, which is accompanied by 
febrile temperature and causes heavy mortality. The popular desig- 
nation “cholera” is frequently used to indicate any highly destruc- 
tive disease of poultry. 
Etiology. The causative organism is a member of the septi- 
cemia hemorrhagica group and has been designated by various names, 
among them, Bacillus avisepticus, B. bipolaris septicus, B. avicida, 
B. cholere gallinarum, and Pasteurella avium. A strain isolated 
by Ward possessed the following characteristics: 
“ Morphology. The individual cells are short, non-motile rods, with 
rounded ends. They usually occur singly, but a few are seen in pairs. 
Spherical forms are numerous in actively growing cultures. The size 
varies from .4 to .6 micron broad and from 1 to 2 microns long. A bipolar 
arrangement of the protoplasm is demonstrated when carbol fuchsin and 
alkaline methylene blue stains are used. The bipolar staining is notice- 
able frequently in smear preparations from tissues. The presence of a 
capsule is suggested by an unstained area surrounding each organism when 
a background of stain is deposited upon the cover glass. The same appear- 
ance is noticeable in smear preparations from tissues. The organism re- 
tains the stain but faintly when treated after Gram’s method. 
* Biologic Characters. The organism is aerobic and facultative anaero- 
bic. It grows readily at 37.5° C., and with much less rapidity at room 
temperature. 
“Agar. The colonies on one per cent agar, after forty-eight hours incu- 
bation at 87.5° C., appear as round, smooth, thin, shiny disks, with entire 
border and measuring about 2 mm. in diameter. Under a two-thirds ob- 
jective they appear coarsely granular and show concentric circular markings. 
They appear smoky brown in. color by directly transmitted light, and gray 
by reflected light. Colonies beneath the surface are usually lenticular in 
shape, and the granular appearance is more marked under a two-thirds 
objective than in the surface colonies. After twenty-four hours the growth 
on the agar slant culture is flat, smooth, shining, translucent, grayish 
white by reflected light, and smoky brown by transmitted light, with un- 
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