172 Influenza o£ Horses. 



Babes, Starcovici & Calineseu (1889), as well as Galtier & Violet (1890), 

 demonstrated in the tissue of affected lungs bipolar staining bacteria, 

 besides the diplococcus of Schutz. They suggested the etiological 

 relation of this organism; Lignieres (1897 to 1900) established its 

 identity with the causative organism of hemorrhagic septicemia, and 

 expressed his view that influenza is caused by these bacteria, while 

 the diplococcus of Schiitz plays an insignificant part in the etiology 

 of the pathological processes. Exception may also be taken to this 

 view, the same as against those of Schiitz, and it may especially be 

 mentioned that with neither of these two bacteria may a typical pneu- 

 monia be produced, as well as that the bipolar bacilli probably exert their 

 pathogenic action only secondarily in the affected animal ; therefore the 

 question of the true cause of influenza, or of its two f^rms, must be 

 considered at the present time as unsolved. 



Occurrence. Tlie disease occurs everywhere either sporad- 

 ically, or in a pronounced enzootic form, and in the latter case 

 it spreads rapidly among the horses of large territories. With 

 the greatly varying character of the disease it sometimes causes 

 only slight losses, while at other times a considerable percentage 

 of the affected animals succumb to the disease, principally as 

 a result of pleuro-pneumonia which develops in its course. 

 Owing to the latter condition the disease is of great economic 

 importance, but the owners also sustain considerable loss 

 in the milder outbreaks as a result of the incapacity of the 

 horses for work. 



Large outbreaks occurred in Europe during the last century in the years of 

 1813-1815, 1825-1827, 1836, 1846, 1851, 1853, 1868, 1870-1873 (in connection with 

 the German French war), and finally in the years of 1881-1883, at which time the 

 disease spread over almost the entire continent. In 1872-1873, the disease occurred 

 extensively in America; starting in the eastern parts it extended all over the 

 United States. It was introduced in South Africa by the English troops in 1899. 



In 1908 the reports from the German Empire show in Prussia 622 deaths from 

 the disease; in Bavaria and Saxony 55 and 210 cases resp., were affected with the 

 pleuro-pneumonic form, while 12 and 48 cases respectively were affected with the 

 catarrhal form. In Wurttemberg 88 cases with 12 deaths resulted from the disease. 

 However, these numbers are not considered as complete. 



Among the horses of the Prussian army, in the years between 1899 and 1908, 

 861, 4,325, 1,066, 594, 2,223, 1,367, 487, 1,811, 8,058, and 1,010 horses, were 

 affected with the catarrhal form, while the pleuro-pneumonic form occurred in 2,301, 

 1,608, 1,078, 1,937, 1,263, 1,675, 3,877, 7,581, 3,502, and 2,750 horses, respectively. 



Etiology. The true primary cause of the disease has, up 

 to the present time, not been established. Bacteriological ex- 

 aminations prove only the fact that in the pectoral form (con- 

 tagious pleuro-pneumonia) two bacteria are principally pres- 

 ent, the streptococcus, pyogenes equi, and the bacillus equi- 

 septicus. 



I. The streptococcus pyogenus equi, which has been de- 

 scribed by Schiitz as the cause of contagious pleuro-pneumonia, 

 under the name of diplococcus pneumoniae, is in its principal 

 character identical with the streptococcus of strangles, or at 

 least is closely related to the same. In the affected tissues 

 it is present in the form of mono and diplococci ; in the exudates 

 in somewhat longer chains. It stains readily with aqueous 



