580 The Blood Flagellates 



that flagellates from naturally infected sandflies induced typical oriental 

 sore when inoculated into man (4). After feeding upon these lesions, sand- 

 flies developed flagellate infections. These flagellates, in turn, induced 

 typical sores upon inoculation into man. The second crop of sores again 

 was infective for sandflies. In later work on kala-azar, hamsters were in- 

 fected by oral introduction of L. donovani (63) and later by ingestion of 

 infected sandflies (65). In 1931, L. donovani was transferred to a hamster 

 by the bite of a sandfly under experimental conditions (64). Some of the 

 earlier difficulties in producing heavy mfections of sandflies have been 

 largely eliminated by better diets for the flies, and kala-azar can now 

 be transferred readily to hamsters (67, 68). Such techniques also have 

 made possible the vector transfer of kala-azar to human volunteers (69). 

 Similarly, the experimental transfer of L. tropica by sandflies has been 

 facilitated by adding salt to the diet of the flies (3). 



Diagnosis 



Blood films, and smears of other tissues (splenic pulp, bone mar- 

 row, liver, lymph glands) obtained by puncture methods, may be ex- 

 amined directly for L. donovani. Spleen smears are probably positive in 

 at least 80 per cent of the actual infections, and sternal puncture is 

 equally reliable (49). The results of the two methods agree closely (30), 

 and sternal puncture has the advantage of being less dangerous. Thick 

 blood smears are somewhat less reliable than smears from the spleen and 

 bone marrow. In any case, diagnosis may be difficult in early stages of 

 kala-azar, and prolonged search of smears may be necessary. In diagnosis 

 of dermal leishmaniasis, the parasites are best detected in material aspi- 

 rated from the periphery of the lesion, from the tissues just beneath the 

 ulcer, or from non-ulcerated nodules. L. brasiliensis is most abundant in 

 the early lesions of the skin and mucosa and may be found also in lymph 

 glands adjacent to sores. It is usually difficult to recover the flagellates 

 from old bacterized sores. 



Culture methods, for the experienced worker, are generally more reli- 

 able than tissue smears in diagnosis of kala-azar and may be preferable 

 where facilities are available. Aseptic precautions are required, and for 

 best results, blood agar slants may be inoculated with leucocytes centri- 

 fuged from 5-10 ml of blood. Upon incubation at 22-25° C, a heavy 

 growth of flagellates may be expected within 72 hours. With the addition 

 of penicillin for the control of bacteria, culture methods also appear to 

 be satisfactory for demonstrating L. tropica m bacterially contaminated 

 lesions (43). This technique may prove useful likewise in diagnosis of 

 kala-azar. 



Several indirect tests for kala-azar are based upon the characteristic 

 increase in serum globulins. In Brahmachari's test the addition of 2-3 

 volumes of distilled water to one of kala-azar serum precipitates the 



