Foivl Cholera, Fowl Typhoid and Fowl Plague 107 



zling question. Thus while many epidemics owe their origin 

 to the importation of infected birds, birds returning from 

 poultry shows, or to the presence of infected wild birds, some 

 epidemics appear to arise spontaneously. Recently it has 

 been foinid that the causative organism is occasionally 

 present in the intestines of an apparently healthy bird. 

 These spontaneous epidemics are probably to be explained as 

 due to the increase in virulence of such organisms. After 

 passage through two or three hens this virulence is still 

 further increased so that an epidemic is started. Later on 

 this same strain may decrease in virulence but may remain 

 in the flock only to break out again a year or two later. 



Within the flock the infection is generally transferred 

 through the food or drinking water contaminated with the 

 excrement of sick birds. It is also possible for birds to be 

 infected through wounds of the skin or by inhalation of the 

 germs in the form of dust suspended in the air. In other 

 cases the dissemination of the disease is undoubtedly due to 

 the fowls eating the dead bodies of infected birds. 



Treatment. — At the present time there is no certain cure 

 known for fowl cholera after the bird has been infected. 

 While some birds may recover of their ow^n accord it is prob- 

 able that such birds are a source of danger to the flock for 

 some time afterwards. Miiller ^ states that infected fowls 

 continue giving off the bacteria in the urates three weeks 

 after infection, and that the organs contained virulent mate- 

 rial after a period of six months. 



Under ordinary circumstances, if it is known that fowl 

 cholera is on the premises, every bird showing marked symp- 

 toms of this disease should be killed at once. The birds 

 should be killed in such a manner that their blood will not 

 be spilled near the houses or runs. Every drop of blood from 



1 Miiller, J., "Monatsh. Prakt. Tierheilk." Bd. 21, pp. 385-413, 

 1910. 



