856 



Infectious Anemia of Horses. 



in the fat or gelatinous marrow, especially in the femnr and 

 humerus was already indicated by Skiba. 



In acute cases of the disease the blood shows no peculiar 

 macroscopical changes with the exception of slower coagula- 

 tion, while in the more chronic cases indications of an anemia 

 appear. This is increased in proportion to the duration of 

 the disease. Moderate edematous infiltrations of the subcu- 

 taneous, perirenal, as well as in the intermuscular connective 

 tissue between the mesenteric layers, further icteric discolora- 

 tion of the tissue are not infrequent occurrences, Avhile marked 

 emaciation is frequently observed. 



Symptoms. The period of incubation after a subcutaneous 

 or intravenous infection varies between five and nine days, 

 and may also be the same after an intensive natural infection. 

 Ordinarily however it probably lasts for 2 to 3 weeks, as was 

 noted in the experiments of Ostertag and Marek (see p. 854). 

 With respect to the duration and the symptoms, two clinical 

 forms of the disease may be recognized to good advantage, 

 between which however no sharp line can be drawn, and con- 

 sequently Carre & Vallee have even described a subacute form. 



The acute form appears quite suddenly with distinctly 

 pronounced symptoms. A conspicuous depression and general 

 weakness develops, as a result of which the animals rapidly 

 tire, and sometimes even fall down while in motion. Then 

 they rise only with great difficulty or can regain their feet only 



Fig. 153. Fever curve in the acute form of infectious anemia of horses. 



with human assistance. At the same time the weakness, as 

 in all general infectious diseases, is distinctly noticeable in the 

 hind parts. Frequent tripping, or an uncertain use of the 

 hind leg may also be observed quite frequently. Sometimes the 

 position of the body is similar to that in laminitis. 



Fever sets in at the same time (see Fig. 153), and after 

 a gradual rise of the temperature, reaches its height on the 

 second or third day (40-40.5°, sometimes even 42° [Carre 



