FOWL CHOLERA 587 



Symptoms. The period of incubation varies somewhat, 

 no doubt due to the mode and virulency of the infection. 

 It is usually one to four days; occasionally longer, four to 

 seven days. Fowl cholera is characterized by its sudden 

 onset and the rapidity of its course. When it first appears 

 in a flock, birds will drop dead apoplectically without show- 

 ing symptoms. They may be found dead beneath the roost, 

 or on the nest. Some of them when attempting to walk or 

 fly will drop suddenly and die after a brief struggle. After 

 the disease has been in a flock for a few days, the less sus- 

 ceptible will show some marked symptoms. The birds 

 lose their appetite, become weak and greatly depressed. 

 The wings are usually pendent, the neck curved and the 

 head pulled downward. The entire plumage becomes ruffled 

 and the birds walk with a weak, staggering gait. The 

 temperature is elevated 2 to 4 F. above normal. Diarrhea, 

 accompanied by intense thirst, becomes a prominent symp- 

 tom. The droppings are at first of a yellowish-gray color, 

 later becoming very thin, watery, fetid, of a greenish cast 

 or dark green. The feathers around the cloaca become 

 soiled and matted with the bowel discharge. Marked 

 dyspnea sets in, the bird opening and closing its mouth 

 during respirations; wheezing and rhonchi are frequently 

 heard. The comb and wattles are dark bluish (cyanotic). 

 The bird finally becomes very weak, staggers about, falls 

 down, and dies in coma or convulsions. In the chronic 

 form of the disease the course is much longer. The bird 

 grows anemic, emaciated and cachectic. Frequently the 

 joints are enlarged; the joint capsule may rupture and dis- 

 charge a seropurulent material. Death results from exhaus- 

 tion. The course in this form may extend over a period of 

 several weeks. 



Diagnosis. There are a few conditions in birds that 

 might be confused with cholera, as the symptoms are similar. 

 An accurate diagnosis is only possible on finding the typical 

 bacilli. However, the symptoms and pathological findings 

 should assist in making a diagnosis. A differential diagnosis 

 must be made from ptomain poisoning which is very com- 

 mon in birds, and which frequently kills a large number in 



