LEISHMANIA DONOVANI 401 



lymphatic glands, pigmentation and dryness of the skin, and oedema. 

 These may be ascribed to the general malnutrition, while dysentery, 

 cancrum oris, and pneumonia are complications due to secondary bacterial 

 infections. Left untreated, the disease nearly always ends fatally, though 

 a small percentage of recoveries may take place. Recovery has also been 

 noted after certain bacterial infections, which seem to act adversely on 

 the leishmania. The duration of untreated cases may be only a few 

 months in acute forms of the disease, or several years in the more chronic 

 type. 



RELATION OF INDIAN KALA AZAR TO THE SIMILAR DISEASE IN 

 OTHER LOCALITIES. — Kala azar was first recognized as a distinct disease 

 in India, but after the discovery of the characteristic leishmania as its cause, 

 it was soon found to have a much wider distribution. The discovery of 

 kala azar in the Mediterranean area as a disease which afiected chiefly very 

 young children at once raised the question of its identity with that of 

 India. The parasite causing the Mediterranean type of the disease known 

 as infantile kala azar was named Leishrnania infantum by Nicolle (1908). 

 The discovery of the disease in the Caspian region and in the Sudan, 

 where children and young adults are mostly affected, and the realization 

 that in India it is by no means limited to adults, as at one time was 

 supposed, have raised doubts as to the validity of the species L. infantum. 



Morphologically, there is no distinction between the leishmania from 

 the various areas in which the disease occurs, nor is there any marked 

 difference in which animals respond to inoculation. In the Mediterranean 

 and Caspian areas, the disease is associated with a similar one in dogs, 

 whereas in India kala azar in dogs has not been discovered, though it has 

 been very carefully looked for. It is known, however, that dogs can be 

 infected with the Indian parasite. There seems no r-eason, therefore, 

 to separate the Mediterranean leishmania from that of India, and the 

 parasite of kala azar, wherever it occurs, wall be designated Leishmania 

 donovani. Noguchi (1924) has found that serologically L. donovani and 

 L. infantiim are identical. 



PATHOLOGY. — The chief histological change in the organs of kala azar 

 cases is an increase in the large macrophages, which are presumably 

 derived from the endothelial cells of the capillaries. Correlated with 

 this is an increase in the proportion of mononuclears in the blood, though 

 the general leucocyte picture is usually one of leucopenia. The very much 

 enlarged spleen shows an increase in fibrous tissue, and a multiplication 

 of the macrophages, which are often loaded with parasites (Fig. 186). 

 Similar changes occur in the liver, where the fibrotic change may be very 

 marked, while the bone marrow shows a great increase in these large cells 



I. 26 



