Calf Diphtheria. 4;l^9 



Simultaneous inoculations with serum of highly immunized sheep 

 (•1 ce.), and with virulent blood (2 cc), gave very favorable results in 

 a herd of 295 merino sheep. A mixture of serum and virus (2 :1) is also 

 suitable for immunization. Theiler observed that in serial inoculations 

 of sheep the virulence diminishes gradually and finally from the tenth 

 operation, and from then on, a harmless vaccine is obtained. 



Literature. Spreull, J. of eomp. Path., 1905, XVIII, 321.— Paine, Ibid., 1906 

 XIX, 5.— Theiler, Schw. A., 1895, XXXVII, 1: Bull. P., 1905, III, 617; Z. f. Tm ' 

 1907, XI, 301. 



4. Calf Diphtheria. Diphtheria vitulorum. 



{Angina diphtheritica vitulorum.) 



Calf diphtheria is an acute infectious disease of sucking 

 calves, in the course of which croupous diphtheritic pseudo- 

 membranes form on the mucous membrane of the mouth and 

 the pharynx, and which, as a result of a general septic infec- 

 tion usually results in death. The causative factor of the dis- 

 ease is the bacillus necrophorus, which was closely described 

 by Bang. 



History. The disease was first described in 1877 by Dammann, 

 who observed it in ejizootic extension in two consecutive years on an 

 estate near the East Sea. He established its contagious and transmissible 

 nature and considered it identical with diphtheria of man. Later 

 Blazekovic and Vollers observed similar affections, while Lofifler (1884) 

 proved by histological examinations that the affection differed from 

 human diphtheria, and was probably caused by long rods, which were 

 present at the border of the necrotic tissue. Later Bang (1890) estab- 

 lished the identity of the Loffler 's bacillus with his bacillus necrophorus. 



Occurrence. According to the observations made up to 

 the present time the disease occurs but rarely; in some localities 

 however it occurs as a stable disease 

 among the sucking calves and causes 

 by its malig-nant course material loss. 

 Thus in Dammann 's case all calves 

 born in the Avinter and spring became 

 affected, and with a few exceptions 

 they died of the affection. 



Etiology. The bacillus necro- 

 phorus. Bang, which is considered to 

 be the cause of the disease, appears as 

 a thin slender rod, which in the tis- 

 sues as well as in artificial cultures, 

 grows into long threads, the plasma of l'^- ^^- , BadUus necrophorus 



'='-..-,. -n 1 1 Banq. Agar culture; staining 



which IS either homogeneous or at with methylene blue. 



uniform distances contains dark, fine 



granules (Fig. 64). The bacillus shows no motility. 



Staining. The bacillus stains only slightly and uniformly with 

 aqueous solutions of aniline dyes, stains well with carbol-fuchsin, but not 

 with Gram. 



