308 DISEASES OF TRUE INFECTION 



Piroplasma Canis, Malignant Jaundice. — This is an infectious, 

 not contagious disease, due to the presence of a protozoon, piroplasma 

 canis, in the red corpuscles; this disease is generally found in warm 

 climates, particularly South Africa; it is very rare in Europe. 



Etiology. — The cause of this disease was first described JDy Plana and 

 Gali-Valerio as a protozoon of the order of hemosporidia, and was carried 

 into the blood of the dog by means of ticks — in France by the Dermacenter 

 reticulatus, in South Africa by the Hemophysalis leachi, and in Germany 

 and Hungary by the Ixodis ricinus reduvious. The disease appears 

 about thirty-six hours after infection of the red blood corpuscles; the 

 corpuscle being colorless, the protozoa can easily be recognized if the 

 blood is fixed with absolute alcohol and stained with methylene blue (Fig. 

 99). The size of the parasite varies from 0.7 to 3.4/i. They multiply 

 very rapidly, particularly when the fever is high. After the destruction 

 of the erythrocytes, the parasites appear in the plasma, and are more 

 rounded in form, and then they appear in greater numbers in the in- 

 ternal organs, particularly in the lung tissue, than in the blood. Trans- 

 mission, either by subcutaneous or intermuscular injection of the de- 

 fibrinated blood containing the parasites, reproduces the disease and 

 the animals die in a week; recoveries are very rare. The blood if kept 

 in a cool place retains its full activity for twenty-five days, in warm 

 weather the infected blood loses its activity in fourteen days, at a 

 temperature of 44° it loses its power in one and one-half hovirs, and at 50° 

 in one-half hour. Young dogs seem more receptive of the disease 

 than older animals; bitches which have had the disease give their 

 puppies a certain amount of immunity from the disease. 



Pathological Anatomy. — If the disease is very acute, and runs a 

 short course, with the exception of the alteration of the blood, very little 

 change is noticed. In more gradual cases there is anaemia, jaundice and 

 great enlargement in the volume of the spleen — it is frequently found 

 to be four times its natural size — hypersemia of the liver, kidney and 

 marrow of the bones, extravasations in the pericardium and in the lungs, 

 catarrh of the stomach and of the intestines, especially the duodenum. 

 In the kidneys, spleen, marrow of the bone, as well as the blood, 

 numerous piroplasma are found. 



Clinical Symptoms. — The disease occurs in both acute and chronic 

 forms. The acute form is ushered in by listlessness, depression, want 

 of appetite, and increase of temperature to 40-43°, and a few days 

 later by a rapid fall of temperature to sulmormal; the visible mucous 

 membranes are cyanotic, sometimes yellow, icteric; the pulse and 

 respirations are increased and frequently labored; the gait sluggish 

 and staggering, and finally there is complete paralysis. The urine con- 

 tains albumin and biliary i)igment, and in the majority of cases from 



