ENCEPHALITOZOON 755 



confused with encephalitis lothargica. Later in the year Levaditi, Nicolau and 

 Schoen (1923) also saw the organism, and recognized it as the cause of an ence- 

 phalitis of rabbits which had no connection with the human disease. They gave it 

 the name Encephalitosoon cunieuli, and expressed the opinion that it was a micro- 

 spordian. Doerr and Zdansky (1923rt, b) then gave a clear description of the 

 organism. They noted that it occurred in the form of spores, which were either 

 distributed through the tissues of the brain or collected together in cysts. Levaditi, 

 Nicolau and Schoen {1924a) have given a complete review of the subject and de- 

 scribed their own results. They were able to inoculate the organism to rabbits, rats, 

 mice, and dogs. In rabbits it was found only in the brain and kidneys, though 

 Wright and Craighead (1922) had observed it also in the spleen, liver, and myo- 

 cardium, as also in the urine, which suggested to them a possible source of infection. 

 Levaditi and his co-workers have actually demonstrated the infectivity of the urine. 



'7% 





Fig. 323. — Encephalitozoon cunieuli in Atrophying Nerve Cell and scattered 



THROUGH THE BrAIN SUBSTANCE ( x 1,200). (AfTER Da FaNO, 1924.) 



During the course of their experiments they (1924) discovered that mice were liable 

 to a similar infection. Cowdry and Nicholson (1924) have also observed an organism 

 in mice, which appears to be morphologically identical with that in rabbits, and gives 

 rise to similar lesions in the central nervous system. The lesions consist of menin- 

 gitis of the cortex and septa of the brain, perivascular infiltration of the blood- 

 vessels, and nodules composed of masses of cells which may be necrotic centrally. 

 Marked changes occur in the kidneys, especially in the heavily infected epithelium 

 of the tubules, and in the liver and spleen. 



In the infected organs the parasites are either scattered through the tissues or 

 enclosed in masses in what are called cysts (Figs. 322, 323). It appears more probable 

 that these are the remains of endothelial or other cells, for often a large flattened 

 nucleus can be seen on the cyst wall. In fact, Wright and Craighead describe the 

 infected cells as being reduced to membranes containing the organisms. By the 

 rupture of the enclosing membrane the spores are scattered through the tissues. 



