116 Diseases of Poultry 



disease has been reported in many other places within the 

 last few years. It thus seems certain that the disease is 

 widespread throughout the United States and Canada and 

 in the future must be reckoned with by American poultry- 

 men. 



Tuberculosis may exist extensively among fowls, especially 

 in large flocks, and yet not kill enough birds to attract 

 attention to it. Reports show that farmers often lose one or 

 two birds a year from what appears to be tuberculosis. In 

 many places the loss seems to be gradually increasing. The 

 existence of the disease in the flock fails to attract the atten- 

 tion of the owner because the losses are so evenly distributed 

 throughout the year. In other cases the disease appears to 

 be more virulent and to cause very serious losses. Moore 

 and Ward report a flock of 1400 birds from which 250 had 

 died during the first year. Another man lost 300 birds out 

 of a flock of 1460. Microscopic examination proved that 

 these were dying of tuberculosis. 



Tuberculosis is confined chiefly to adult or nearly adult 

 fowls. Only very rarely, if ever, is it found in growing chicks. 

 Further it is much more common in fowls than in other kinds 

 of poultry. Two cases in wild geese were reported at the 

 Ontario Agricultural College. Avian tuberculosis is said 

 to be found in turkeys, pheasants, and especially in pigeons. 

 Cage birds are particularly susceptible to this disease. 



Etiology. — Tuberculosis is caused by a minute germ, 

 the Bacillv^ tuberculosis of birds. These bacteria gain 

 entrance to certain portions of the body and there multiply 

 in vast numbers, causing the formation of small nodules or 

 tubercles. The disease is highly contagious and is spread 

 through the flock by the contact of healthy birds with the 

 diseased ones, or with their discharges. 



The relation of avian tuberculosis to that of man and other 

 animals has attracted a great deal of attention. It is a 



