424 MAL DE CADKRAS 



water hogs suffering from mal de caderas. It is transmissible 

 to white and gray rats and mice, rabbits, dogs, goats, sheep, 

 chickens, turkeys, ducks and certain monkeys found in South 

 America. Cattle are said to be immune. 



The parasites are most numerous in the circulating blood 

 during the rise of temperature. Upon its reaching 40-41° C 

 they gradually disappear, but reappear with the next rise of 

 temperature. 



§ 329. Mode of infection. Unlike dourine, the virus of 

 mal de caderas is not transmitted by copulation. It has been 

 proven that the virus is disseminated and animals are infected 

 with it by means of certain insects. Stomoxys calcUrans has 

 been incriminated and several other insects are under 

 suspicion. 



§ 330. Symptoms. The first symptom is an elevation 

 of temperature which rises slowly, but suddenly falls to nor- 

 mal. Emaciation is rapid. The urine is dark colored and 

 usually contains albumin, and perhaps blood. The blood 

 changes so that it gives the picture on microscopic examina- 

 tion of pernicious anemia. There is an increase in the lym- 

 phocytes and in the eosinophiles. The most obvious symptom 

 is said to be a symmetrical or asymmetrical paresis of the hind 

 legs. Defecation and urination are difficult (coinciding with 

 paralysis of the sphincters). The paralysis gradually extends 

 to other parts of the body. Edema is often present. The 

 appetite remains good until near the end when there is 

 extreme thirst. 



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. 



§ 331. Morbid anatomy. The muscles are pale and 

 atrophied in the posterior part of the body. The intermuscu- 

 lar tissue is infiltrated with a gelatinous serous-like substance. 

 Hemorrhagic foci appear in the muscles of the rump. 



Digitized by Microsoft® 



