836 Mai de Caderas. 



The natural mode of infection has not yet been elucidated. 

 At first it was thought that stinging flies were the transmitters 

 of this disease, especially the stomoxys brava (Mosca brava) 

 and tabanidae as well as possibly also mosquitoes (Lignieres& 

 Zabala, Voges) ; according to the observation of Elmassian & 

 Migone, however, horses which are separated from affected ani- 

 mals only by a fence remain healthy in spite of being swarmed 

 by stomoxys flies. 



Later the last-named authors connected a rodent with the appearance of the 

 disease (Hydrochoerus capibara, vulg. Carpinoho), observing that these animals 

 sometimes die in great numbers, and that hunting dogs which have eaten their 

 flesh also become affected, whereupon the disease soon breaks out among horses. 



Anatomical Changes. These consist usually in an acute 

 swelling of the spleen and the lymph glands, accumulation of 

 sero-fibrinous exudate in the serous body cavities and in the 

 joints, hemorrhagic nephritis, parenchymatous degeneration of 

 the internal organs, besides hemorrhages and serous infiltra- 

 tion of the muscles of the croup. 



Symptoms. A weakness of the hind parts is noticeable 

 from the onset of the disease, as the animals show a staggering 

 gait, bringing forward the hind legs, dragging them on the 

 ground, and frequently knuckling in the tarsal joints. With the 

 rapidly progressing emaciation, the paraparesis reaches a very 

 high degree, so that the patients rise from the ground with 

 difficulty, after which they stand with legs spread apart, and 

 can not be made to move. Finally they are unable to rise, 

 and then the sphincter ani becomes relaxed and the rectum 

 fills with balls of feces or defecation becomes involuntary. 



The body temperature shows a febrile elevation atypical 

 in character, urticaria-like swellings appear on the skin which 

 become covered with small crusts; subcutaneous edemas are 

 observed but rarely, and then only on the lower abdomen, while 

 ,,. swelling of some of the joints is frequently observed. The 

 urme -eontains albumen and frequently some blood, the latter 

 sometimes in great quantities. Inflammation of the conjunc- 

 tivae and:;Cornea is a frequent complication. The appetite re- 

 ni^ins good until the end. 



^\ The course is always unfavorable. After the appearance 

 . ^f tie disturbances in locomotion the animals usually succumb 

 --in 1 to 2. inonths, but there is also a chronic form of the affec- 

 tion (known in Paraguay as Baacy-poy=slow emaciation), 

 which develops very graduailly, so that the emaciation and weak- 

 ness of the hind parts becomes apparent only after months. 



Trypanosomes are found in the blood only in acute cases 

 in considerable numbers, while otherwise their demonstration 

 is successful only by inoculation of test animals (mouse, rat). 



The disease runs under similar manifestations in mules 

 and asses. 



