852 Infectious Anemia of Horses. 



and Denoc (1843), and was associated with conditions of feeding, the 

 more so as later Delafond (1851) failed in its artificial transmission. 

 Its infectious nature was first indicated by Anginiard (1859). Later 

 Zschokke (1883) reported several cases of pernicious anemia observed 

 by him in Switzerland, which in part developed as an outbreak, and 

 clinically as well as anatomically completely corresponded with the 

 infectious anemia, the same as the cases observed somewhat later by 

 Frohner (1886) and Ostertag (1890) in Germany. As a matter of 

 fact Frohner considered the pernicious anemia of horses even at that 

 time as an infectious disease. The nature of the disease was clearer! 

 up in all details by Carre & Vallee (1904-1906) ; further eontrilaitious 

 on the disease were furnished by Ostertag (1907), Marek (1907) and 

 Hempel (1909). 



Ekwall (1895) described an enzootic anemia of horses in Sweden, 

 which also corresponded with the infectious anemia clinically and 

 anatomically, but its identity with infectious anemia cannot be estal)- 

 lished positively for the reason that Brickmann recently (1904-1906) 

 demonstrated parasites in the blood in a similar affection of horses. 



Occurrence. The disease is observed among horses, al- 

 though other solipeds may he infected artificially, and it is 

 probable that they may here and there become also affected 

 by natural infection. It appears in more or less circumscribed 

 localities, in the first place in marshy places, usually as 

 a disease confined to single or several adjoining premises, and 

 causes considerable economic loss because the disease as a rule 

 leads sooner or later to death. Sporadic cases of the disease 

 may also be observed, namely, through the introduction by 

 newly purchased affected or infected horses, which then under 

 certain conditions may alone become affected, while the other 

 animals of the premises may be spared. 



In France infectious anemia prevails in the northeastern territories, above 

 all in the entire valley of the Meuse, further in the districts of Anbe, Marne, 

 Cote-d'Or, Meurthe-et-Moselle, and was recently observed by Dupas also in Chalons. 

 In some of the localities it causes very great losses, which according to Vallee are 

 estimated for the Department at 200,000 francs annually. 



In Germany the disease occurs less extensively than in the adjoining terri- 

 tories of the infected French districts, especially in Lorraine (Kopke, Jarmatz, 

 Ostertag), further in the district of Trier. Hochstein observed it in a horse stable 

 in Bavaria. 



In Hungary the disease was established by Marek upon three premises in 

 three different counties. 



From wliat was already said it appears that the disease occurs also in 

 Switzerland and probably in Sweden. It was likewise observed in Mexico. 



To all appearances infectious anemia of hors-es has a far greater geographical 

 distribution than appears from the data mentioned, only it is frequently confounded 

 with other internal diseases. Thus in certain cases the so-called skalma is probably 

 as a matter of fact an infectious anemia. 



Etiology. The fundamental investigations of Carre & 

 Vallee, the results of which w^ere later fully confirmed by Oster- 

 tag and Marek, show^ed that the contagion of infectious anemia 

 belongs to the ultra-microscopical microorganisms. The virus 

 passes the porous (Chamberland-Berkefeld) porcelain filters 

 and cannot be demonstrated by staining methods or by cultiva- 

 tion. 



