758 PATHOGENIC PROTOZOA 



The parasite is probably transmitted by some insect, either cimex 

 (Rogers), or by the dog flea, Ctenocephalus canis (Wenyon), or a 

 plant-feeding bug, Conorhinus y which occasionally sucks blood. 



Animal Pathogenicity. Wenyon in 1913 1 inoculated a dog with 

 splenic emulsion from a man who died in London of kala-azar con- 

 tracted in Calcutta. The parasite has been successfully carried 

 through five animals, and in 1915 an examination of the bone marrow 

 showed not only typical leishmania, but also a few large, well-marked 

 leptomonad forms. Similar forms were described by Escomel in 1911, 

 from South American dermal lesions. Monkeys may also be infected. 



Leishmania tropica (Delhi or Aleppo boil) is the organism found 

 in a local skin affection variously termed Delhi boil, Aleppo boil or 1 

 tropical ulcer. While it is probably transmitted by some insect, there 

 is as yet no definite proof. The incubation period is about two 

 months, while the disease, once manifest, lasts twelve to eighteen 

 months and is followed by immunity for life. 



The parasite, which was first described by J. H. Wright. 2 shows 

 minor differences from Leishmania donovani, particularly a variable 

 morphology, all gradations, from the usual oval to elongated narrow 

 forms with pointed ends, being found. 



Cultures may be obtained on the N. N. N. blood agar, which develop 

 into leptomonads, as with Leishmania donovani. Dogs and monkeys 

 are susceptible to artificial inoculation, and it is possible that in nature 

 the disease is carried from dogs to human beings by some insect. 



Leishmania infantum (Infantile Splenomegaly) was described 

 by Nicolle in 1909 from cases of infantile splenomegaly occurring in 

 Northern Africa. The disease resembles kala-azar in all respects, except 

 that the patients are young children, and it is possible they are the 

 same disease. The parasites are found in abundance in the liver, 

 , spleen and bone marrow at autopsy and may be cultivated in the usual 

 way on the N. N. N. blood agar. 



Animal Pathogenicity. The disease occurs naturally in African 

 dogs, and they are probably the source of infection, the parasite being 

 carried by a flea or some other insect. Dogs, monkeys and guinea-pigs 

 are susceptible to artificial inoculation. 



The treatment of leishmaniasis is unsatisfactory since there is no 

 known specific. 



1 Wenyon, Jour. Trop. Med. and Hyg., London, 1915, xviii, 218. 



2 Wright, J. H., Jour. Med. Res. Bost. 1903, x, 472. 



