520 DISEASES OP THE HOESE. 



EDEMATODS PNEUMONIA. 



[Synonyms: Contagious pneumonia; adynamic pneumonia; hospital, or sta- 

 ble, pneumonia ; equine pleuro-pneumonia ; influenza ; pectoralis equoram; pleuro- 

 pneumonia; contagiosa cquorum; hrustseuclie, German.] 



Definition. — This disease is the adynamic pneumonia of the older 

 veterinarians, who did not recognize any essential difference in its 

 nature from an ordinary inflammation of the lungs, except in the 

 profound sedation of the force of the animal affected with it, which 

 is a prominent symptom from the outset of the disease. Again, this 

 same prostration of the vital force of the animal, combined with the 

 staggering movement and want of coordination of the muscles of the 

 animal, caused it for a long time to be confounded Avith influenza, 

 with which at certain periods it certainly has a strong analogy of 

 symptoms, but from which, as from sporadic pneumonia, it can be 

 separated vei-y readily if the case can be followed throughout its 

 whole course. 



Edematous pneumonia is a specific inflammation of the lungs, accom- 

 panied by interstitial edema and inflammation of the tissues of these 

 organs and a constitutional disturbance and fever. It causes a pro- 

 found sedation of the nervous system, which may be so great as to 

 cause death. It is sometimes attended by pleurisy, inflammation of 

 the heart, or septic complications which also prove fatal. 



Etiology. — While, as an infectious disease, its original cause is due 

 to a specific virus, there are many predisposing causes which act as 

 important factors in aiding in its development. Such causes are any 

 influences that lessen the general vigor. 



Old, cold, damp, foul, unclean, and badly drained and ventilated 

 stables allow rapid dissemination of the disease to other horses in the 

 same stable and act as rich reservoirs for preserving the contagion, 

 which may be retained for over a year. 



The virus is but moderately volatile, and in a stable seems rather 

 to follow the lines of the walls and irregular courses than the direct 

 currents of air and the tracts of ventilation. Professor Dieckerhoff 

 found that the contagion of influenza was readily diffusible through- 

 out an entire stable and through any opening to other buildings, but 

 he also found that the contagion of edematous pneumonia is not 

 transmissible at any great distance, nor is it very diffusible in the 

 atijnosphere. A brick wall 8 feet in height served, in one instance, 

 to prevent the infection of other animals placed on the opposite side 

 from a horse ill with the disease, while others placed on the same side 

 and separated from the focus of contagion onlj' by open bars in the 

 stall were infected and developed the disease in its typical form. 



Symptoms. — The symptoms differ slightly from those of a frank, 

 fibrinous pneumonia, but not so much by the introduction of new 

 symptoms as by the want of or absence of the distinct evidences of 

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