MAL DE CADERAS 381 
The duration of the disease is variable. Some animals die after a 
month, others live for a year or longer. Stiles states that it lasts from 
two to five months in horses and from six to twelve months in mules 
and asses. Horses are reported to never recover. 
Morbid anatomy. The muscles are pale and atrophied in the 
posterior part of the body. The intermuscular tissue is infiltrated 
with a gelatinous serous-like substance. Hemorrhagic foci appear in 
the muscles of the rump. 
The spleen and lymphatic glands are enlarged. The liver is 
enlarged and congested. The heart muscle is soft and flabby. The 
lungs often contain ecchymoses and subpleural emphysematous areas. 
There is a serofibrinous exudate in the body cavities, especially in the 
pericardial sac and pleural spaces. There are conflicting state- 
ments concerning the morbid anatomy and it is difficult to select 
statements relative to the lesions that are not contradicted. The 
pathological histology and the lesions in the nervous system do not 
appear to have been described. 
Diagnosis. The diagnosis is made from the intermittent fever, 
emaciation, progressive paresis, anemia, and the finding of the para- 
site. The inoculation of experimental animals (mice or dogs) with the 
blood is of value when the parasite is not found on microscopic 
examination in the blood of the horse. This affection is to be differen- 
tiated from the other forms of trypanosoma infections. There seems 
to be no other specific disease with which it would be confused. 
Morphologically the trypanosome of caderas is distinguished from 
the parasites of nagana, surra, and dourine by the small size of its 
centrosome. Caderas is not propagated in the same way as dourine, 
and moreover, most mammals are susceptible to caderas, whereas the 
number of species susceptible to dourine is very limited. Finally, 
animals which have acquired immunity against nagana, surra, or 
dourine are as susceptible to caderas as normal animals, and vice 
versa. 
REFERENCES 
1. Lecterc. El] mal de Caderas. Buenos Ayres, 1899. 
2. Licnrérms. Contribucién al estudio de la trypanisomiasis de los Equideos Sud 
Américanos. Buletin de agricultura y yanaderia (Republic Argentina), 1902, p. 843. 
3. ResBourceon. Note sur le mal de Cadeiras. Recueil de méd. vét., 1889, p. 85. 
4. Voces. Das mal de Caderas Zeitschrift f. Hygiene, Bd. XXXTX (1902), S. 
323. 
See also literature on other trypanosomata. 
