736 IOWA DEPARTMENT OF AGRICULTURE 



with fowls that are purchased from infected flocks or with the eggs of 

 diseased birds that are obtained for the purpose of hatching. If the 

 disease exists in neighboring flocks the contagion may be carried by 

 small birds or animals passing from one yard to another. A peculiarity 

 of the tuberculosis of birds is that the liver and intestines are nearly 

 always very severely affected, and that as a consequence the bacilli are 

 very numerous in the intestinal contents and are scattered with the 

 droppings everywhere that the fowls go. The introduction of a single 

 diseased bird may, therefore, cause the infection of the greater part of 

 the flock in a few weeks. In the same way, when wild birds contract 

 the disease the bacilli are carried and deposited in all the yards which 

 they visit. 



The eggs of diseased birds frequently contain the bacilli, as has 

 been proven by the inoculation of and transference of the disease to 

 rabbits and guinea pigs. The young chicks hatched from such infected 

 eggs are diseased when they leave the shell and, of course, soon infect 

 the poultry with which they run. Moreover, since the sterile incubated 

 eggs are often fed to chickens, it is clear that even the eggs which do 

 not hatch may introduce the contagion unless they are cooked before 

 feeding. 



Pigs, cats, rats, and mice are especially liable to be infected with fowl 

 tuberculosis from eating the carcasses of birds which have died, and 

 these animals serve to keep up the contagion and may communicate 

 it to other fowls. Even calves and colts are sometimes found suffering 

 from this form of tuberculosis. 



Symptoms. — These are generally not observed in the internal tuber- 

 culosis of fowls until the disease has reached an advanced stage of de- 

 velopment. They begin with gradual loss of weight, wasting of the 

 muscles, paleness of the comb, and toward the end dullness, sleepiness, 

 and diarrhoea. Very often there is at the same time a tubercular in- 

 flammation of the joints and of the sheaths of tendons, which is revealed 

 by lameness, swelling of the joints and legs, and sometimes by the 

 formation of hard, external tumors of considerable size. Occasionally 

 the skin over the swollen joints breaks, the interior of the joint is ulcer- 

 ated, and a small quantity of pus containing large numbers of tubercle 

 bacilli is discharged. Swellings and bony enlargements of the joints 

 with fowls are invariably suspicious, and their nature should always be 

 investigated by killing the bird and examining the liver and spleen to 

 determine if these have any whitish or yellowish spots on their surface 

 which when cut into prove to be tubercular masses. 



Treatment. — There is no treatment that will cure fowls which have 

 been attacked with tuberculosis. When the disease is discovered the 

 effort should be to eradicate it at once by killing off the whole flock and 

 thoroughly disinfecting all the houses and runs. 



As the great majority of the birds will probably be more or less af- 

 fected, the chances are that any which are saved will have diseased 

 livers and intestines, from which the bacilli will escape and keep up 

 the infection of the flock and the runs. The danger of this is so great 

 that no attempt should be made to keep any of the fowls that have been 

 exposed to the contagion, no matter how valuable they may be. The 



