CHAPTER XXXI 

 INFECTIOUS DISEASES OF POULTRY 



Fowl Cholera. — This is a liiglily infectious disease of all 

 species of poultry, that is characterized by weakness, depression 

 and yellowish colored excrement. 



The specific cause of fowl cholera is the Bacillus avisepticus 

 (Fig. 123). This microorganism is transmitted to the healthy 

 birds by the feed, or water becoming contaminated with the dis- 

 charges from the diseased birds. According to Salmon, the 

 period of incubating varies from four to twenty days. 



llie early si/mptojns are a falling off in appetite, high fever, 

 dulness, diarrhcca and weakness. The 

 affected bird becomes drowsy, the head 

 is drawn toward the body, and it may 

 remain asleep for long periods at a 

 time. Salmon states that the general 

 outline of the sick bird becomes spheri- 

 cal or ball-shaped. 



The disease is usually highly fatal. 

 In the acute form the larger portion 

 of the flock mav die off within a week. 



" _ Fig. 123. — Bacillus aiisepticus. 



In the subacute and chronic forms, the 



birds become greatly emaciated, and a few die off weekly through 



a period of a month or longer. 



The tissue changes occurring in the disease are inflammation 

 of all or a few of the internal organs. Ward states that the most 

 characteristic lesion of fowl cholera is the severe inflammation of 

 that portion of the small intestine nearest to the gizzard. Small 

 hemorrhagic spots may be found on the heart and other organs. 



The treatment is J>oth preventive and curative. The pre- 

 ventive treatment consists in quarantining newly purcha:?d 



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