Diseases of the Skin 237 



Chicken Pox {Sore-head or Epithelioma Contagiosum) 



This contagious disease of poultry, although widely dis- 

 tributed in the northern states, is less common and serious 

 here than in the Gulf states and Hawaiian Islands. It is 

 impossible at present to decide whether this is a distinct 

 disease or a form of roup which affects the skin of the head. 

 This can only be determined when further investigations 

 have revealed the real cause of these diseases. Experiments 

 have shown that both pox and diphtheria are easily inoculated 

 from fowl to fowl and from pigeon to fowl, but the inocula- 

 tion of pox from fowl to pigeon has proved very difficult and 

 that of diphtheria impossible. The contagion is believed to 

 exist in the blood as well as in the nodules which appear upon 

 the skin. 



The disease is generally introduced by new birds which are 

 put into the flock or by exhibition birds which return infected. 

 Probably it is often brought by pigeons, sparrows, and other 

 birds which fly from one yard to another. The inoculation 

 of the comb anfl wattles appears to occur by rubbing these 

 parts with the infected feet or by being injured with the 

 infected beaks of other birds. 



The virus is quite resistant and requires thorough dis- 

 infection for its eradication. 



Diagnosis. — The disease usually appears as warty nodules 

 on the unfeathered parts of the head. They look like the 

 tumors in the nasal passages and eye sockets of birds affected 

 W'ith roup. 



Freidberger and Frohner ^ give a good description of these 

 nodules on the skin of the head, as follows : 



"Their favorite seats are those parts of the head that are 

 not covered with feathers ; root of the beak, neighborhood of 



^Freidberger and Frohner, "Veterinary Pathology." (Vol. I. 

 Hayes transl.) Quoted from Gary. 



