P ROTO MONAD ID A 



145 



mucosae; the spleen becomes highly enlarged. The transmitting 

 agent is believed to be blood-sucking arthropods. In culture, 

 the organism develops into leptomonad forms. This genus in- 

 cludes three "species" occurring in man, all of which are prac- 

 tically indistinguishable morphologically from one another, and, 

 two of which are considered as identical. 



Leishmania donovani (Laveran and Mesnil) ( = L. infantum 

 Nicolle) (Fig. 52, a-/). The organism attacks the endothelium 

 and macrophage of man, causing the disease known as "kala 

 azar." It occurs in India, China, west to southern Russia, 

 and shores of the Mediterranean Sea. 



fe 



Fig. 52 a-f. Leishmania donovUni. X2000. (After Wenyon; Thomson and 



Robertson), a, three individuals from lymph smear of a kala 



azar patient; b, from a spleen smear; c-f, cultural forms. 



g, h. L. tropica. X2000 (After Wenyon ; Thomson and Robertson). 



g, from an Oriental sore; n, the parasites in a polymorphonuclear 



cell from a sore. 



Leishmania tropica (Wright) (Fig. 52, g, h). The organism 

 infects the skin of the exposed part and rarely the mucous lining 

 of the mouth, pharynx and nose of man. The resulting disease 

 is usually called "Oriental sore." Distribution is similar to 

 the above-mentioned species. 



Leishmania brasiliensis Vianna. The organism occurs in 

 South and Central America. Some authors consider this spec- 

 ies as identical with L. tropica. Although morphologically 

 identical, these species show specific serum reactions. 



Genus Oikomonas Kent. A monofllagellate rounded or- 

 ganism, living in stagnant water, soil and exposed fecal matter. 

 Uninucleate. Encystment common. 



