KALA-AZAR

in 1881 a malaria-like fever, with great cnlargement of the spleen, was found to be causing serious mortality at the foot of the garo hills in assam, from whence it spread slowly eastward during the next two decades over some 200 m. of the brahmaputra valley, carrying off about one-third of the inhabitants. causation and history of parasite—it was attributed by successive investigators to hookworm disease, epidemic malaria, and malta fever respectively, until in 1903 leishman and donovan independently discovered its cause in a new minute protozoal parasite, leishmania donovani, found in the spleen. in the following year l. rogers developed a flagellate stage of the organism in cultures, and suggested a biting insect, prob- ably the bedbug, as its carrier, a supposition which was sup- ported by patton demonstrating the flagellate stage of the parasite in bedbugs fed on the blood of kala-azar patients in 1905. but in 1925 knowles and napier, of the calcutta school of tropical medicine, appear to have solved the difficult prob- lem by incriminating a sand fly, phlebotomus argentipes, as the true agent in transmitting the discase; this minute insect, to- gether with kala-azar cases, being far more prevalent in areas of calcutta with much vegetation than in the more crowded indian quarter. after the discovery of the causative parasite in 1903 it was soon found that what had for a century been called malarial cachexia in bengal was nothing but a widely distributed sporadic form of the assam epidemic kala-azar, the virulence of the latter being due to its invasion of an areca previously free from the disease. the disease is now recognised as betng very prevalent over all bengal, bihar, the eastern part of the united provinces and in madras, but the comparatively dry punjab and north-west frontier are practically free from the disease, 2 certain degree of humidity being necessary for it. a form of kala-azar especially affecting children is also prevalent all round the mediterranean basin and in egypt and the soudan. symptoms.—\wala-azar is characterised by very prolonged fever, often typhoid-like in the early stages, and frequently show- ing two or three rises and falls in 24 hours, the characteristic double remittent fever, but with long intervals of low continued or intermittent fever, the total duration being seldom less than seven months and often extending, with periods of freedom from fever, over several years; accompanied by extreme wasting, very great enlargement of the spleen, and later of the liver, some anaemia and extreme reduction of the white corpuscles of the blood, which lowers the resisting power of the patients to secon- dary infections with septic diseases, pneumonia, dysentery and phthisis, which are far more frequently the ultimate cause of death than the original disease, the case mortality having been until recently from 80 to 96%p. 629 prophylaxis and treatment.—as the result of his assam re- searches of 1897, l. rogers established a house and site infection of kala-azar and worked out a system of moving the sites of the villages and tea garden coolic lines, whereby the further prog- ress of the epidemic up the assam valley was checked for many years. j. dodds price successfully applied the same plan to ° stamping out the disease from a number of badly infected tea estates, thereby saving the industry in the nowgong district. the debilitating effects of the 1918 influenza pandemic led to a recrudescence of kala-azar in the assam valley, including the more eastern and little infected area. fortunately by this time an effective treatment had been discovered in intravenous injection of tartar emetic and other antimony preparations, which now enables some 90° of the cases to be cured; a greater saving of life perhaps than has been effected in any such fatal illness by modern medical research, with the result that many thousand cases have been treated successfully each year in assam and bengal. given adequate funds and organisation, this, the most terrible of tropical fevers, might be nearly stamped out of the large areas which it has decimated for centuries past and further epidemics prevented. see l. e. napier and e. muir, kala-azar (1923). (l. ro.) kamerun: see cameroons.