MASTIGOPHORA 



757 



* ft 



**< 



Leishmania donovani (Kala-azar). This parasite is the cause of 

 kala-azar, a disease characterized by irregular fever, weakness, anemia, 

 cachexia and a remarkable enlargement of the spleen, and occasionally 

 of the liver. It is 

 chronic, progressive 

 and frequently fatal, 

 the mortality being || 4 



about 80 per cent. 

 The disease .is com- 

 mon in tropical Asia 

 and in northeastern 

 Africa. 



Morphology. The 

 parasite is intracellu- 

 lar, and is found 

 principally in the 

 endothelial cells of 

 the spleen and liver, 

 and in the bone mar- 

 row. It is oval, two 

 to four microns in di- 

 ameter, finely granu- 

 lar and occasionally 

 vacuolated. It con- 

 tains a large, round 

 nucleus and a smaller 

 blepharoplast which 

 is oval or rod shaped ; 

 a third body, a slen- 

 der short thread, may sometimes be recognized, which is presum- 

 ably the undeveloped flagellum. Stained specimens of blood, spleen 

 and liver pulp, and bone marrow, usually show large endothelial cells 

 or leucocytes closely . packed with parasites, one to two hundred to a 

 single cell. Multiplication in the body is by simple division, and 

 incompletely divided pairs of organisms are frequently seen. Cultures 

 have been obtained in citrated blood and on the usual N. N. N. medium. 

 When fully grown the cultural organisms are typical herpetomonads 

 (leptomonads) ; the cell body elongates and the rudimentary, whip 

 develops into a true flagellum. Both dogs and monkeys are susceptible 

 to artificial inoculations. 



FIG. 



178. LEISHMANIA DONOVANI. (Army 

 School Collection, Washington, D. C.) 



Med. 



