The Blood Flagellates 581 



globulins. In Napier's aldehyde test a positive serum forms an opaque 

 coagulum upon addition of a small amount of formalin. Chopra's anti- 

 mony test is a ring test in which a flocculent precipitate develops in the 

 zone of contact between a positive serum and a solution of urea stiba- 

 mine. Although such tests are no substitute for demonstration of the 

 parasites, they have been useful as presumptive tests in field surveys. A 

 non-specific complement-fixation test, using an antigen prepared from a 

 human strain of Mycobacterium tuberculosis, has given good preliminary 

 results with kala-azar, although false positives may be expected occa- 

 sionally in pulmonary tuberculosis (60, 61). 



Chemotherapy 



Prior to 1915 there was no reliable cure for kala-azar and untreated 

 cases had shown a mortality of about 90 per cent in India. Following the 

 introduction of tartar emetic (11), there was a marked change for the 

 better. Introduction of urea stibamine by Brahmachari in 1922 led to 

 further improvement. By 1925, the death rate in India had dropped to 

 about 10 per cent of the cases; in 1928, to about 7 per cent. Neostibosan, 

 introduced a few years after urea stibamine, is more or less comparable 

 in effectiveness. Several more recently tested drugs appear to have real 

 value. Stibatin (sodium antimony gluconate) has given satisfactory re- 

 sults and has fairly low toxicity. Stilbamine seems to be effective against 

 relapsing kala-azar, although its rather high toxicity is an undesirable 

 feature. Stilbamidine, unfortunately too toxic for routine use, has pro- 

 duced clinical cures in about 98 per cent, with a relapse rate of only 

 about 4 per cent. This drug is useful in antimony-resistant and antimony- 

 sensitive cases. Pentamidine isothionate is comparatively harmless to the 

 patient but is not quite so effective as stilbamidine — about 94 per cent 

 clinical cures, with relapses in about 16 per cent. Penicillin has given 

 satisfactory results with "cancrum oris" (noma), a sort of oral gangrene 

 which is a frequently fatal complication of kala-azar. 



In dermal leishmaniasis, intravenous or intramuscular injection of 

 leishmanicidal drugs is usually combined with local treatment for con- 

 trol of bacteria. Since the lesions of oriental sore often tend to heal 

 spontaneously, it is difficult to evaluate the effects of chemotherapy. 



Control of leishmaniasis 



The usual vectors of leishmaniasis are small Diptera belonging to 

 the genus Phlebotomus. These sandflies, or owl midges, are active mainly 

 in twilight and darkness. The females are blood-suckers, usually attacking 

 warm blooded animals. Four or five days after a blood meal, the eggs are 

 laid in moist shaded locations — animal burrows, caves, crevices among 

 rocks, cracks in the soil, or at the bases of hollow trees. The eggs hatch 

 in about a week, and two months or more are required for development. 



