^24 Avian Diphtheria and Chicken Pox. 



of the greatly swollen tonsils are filled with yellowish, brittle masses, 

 and the mucous membrane of the surrounding part is covered with 

 numerous yellowish deposits which may reach the size of a pea, or the 

 diffuse, swollen and reddened, buccal and pharyngeal mucous membrane 

 appears to be covered with caseous deposits. 



A severe pharyngitis, with the formation of pseudo-membranes, has 

 also been observed in dogs and cats (Gray, Symes, Bell), and Brandt 

 reports a case in which a Scotch collie became affected with a diphtheritic 

 inflammation of the throat, and from which he isolated bacteria which 

 microscopically, culturally, and biologically appeared identical with 

 diphtheria bacilli (several days later a girl who attended the dog be- 

 came affected with diphtheria, and 3% weeks later still another girl). 

 During the course of canine distemper, and still more frequently in 

 typhus of dogs, necrotic processes occur on the buccal mucous membrane, 

 which are also caused by the bacillus necrophorus (Jensen), while in 

 one case showing also symptoms of albuminuria and hemorrhages. Ball 

 found only streptococci. 



Literature. Wayr, Bayr. W., 1902, 185.— Strebel, Schw. A., 1899, 173.— 

 Cobbett, Cbl. f. Bakt., 1900, XXVIII, 631.— Diem, W. f. Tk., 1900, 339.— Johne, S. 

 Jhb., 1893, 61.— Kitt, Much. Jhb., 1893-94, 81.— Ball, J. vet., 1906, 449.— Gray, J. of 

 comp. Path. 1896, IX., 46.— Symes, Brit. med. Journ., 1896, I, 1385.— Bell, Amer. 

 Eev. 1901, XXV, 115.— Brandt, J. of the Americ. med. Assoc, 1908, L, 15.— Hasen- 

 kamp, D. t. W., 1909, 237. 



5. Avian diphtheria and chicken pox. Diphtheria et epithelioma 



contagiosum avium. 



Until very recently avian diphtheria was considered to 

 be a contagious, epizootic disease of domesticated fowls, char- 

 acterized by croupous and diphtheritic pseudo-membranes on 

 the mucous membranes of the head, while chicken pox was 

 held to be a contagious, epizootic disease in which hyperplastic, 

 epithelial nodules of the skin occurred especially on the comb 

 and wattles, but in addition to which croupous-diphtheritic 

 deposits frequently developed on the mucous membranes of the 

 head. The two diseases were considered as independent ; more 

 recent research, however, indicates that they are produced by 

 the same organism, and they will here be treated accordingly. 



History. In avian diphtheria as well as in chicken pox investigators 

 were inclined, since the experiments of Rivolta and Silvestrini (1873 

 and 1878), to consider protozoa as the etiological factors (in diphtheria 

 the flagellate, Cercomonas gallinae ; in pox gregarines, hence the former 

 name Gregarinosis). Later bacteriological experiments, particularly 

 those of Loeffler (1884) on pigeon diphtheria, seemed to indicate that 

 the diphtheria was due to a rod-like bacterium which he called Bac. 

 diphtheriae columbarum. Furthermore other observers, as Krajewski, 

 Moore and Galli-Valerio found the same organism in the diphtheritic 

 membranes of sick chickens, while subsequently Guerin demonstrated 

 its identity with the ovoid Ijacillus described by Haushalter and Loir 

 & Ducloux. Streit insisted on the etiological importance of his roup 

 bacillus for the disease called roup in America, and Miiller was of 

 the opinion that the virus of chicken diphtheria was a corynebacillus,' 



