The identification of kala-azar and the discovery of Leishmania donovani.

IN the years following 1858, when the British government formally assumed power over the whole of British India, the government of Bengal became concerned by reports of an epidemic of quinine-resistant fever occurring in the district of Burdwan in Lower Bengal. The mortality was so great that the population, the productivity of the land, and consequently the government revenue were greatly diminished. Some eight to ten years after the epidemic of "Burdwan fever" had been brought to official attention, the Deputy Commissioner of the Garo Hills in south-west Assam reported that a particularly virulent form of fever, which resembled malaria, was decimating the population and that they were asking to be relieved of hut tax as a result. This disease was known locally as kala azar or black disease. Kala azar is characterized by intermittent or remittent fever and enlargement of the spleen; in the later stages there is emaciation, anaemia, and darkening of the skin. Napier and Muir describe the onset as occurring in one of three ways, malarial, typhoid, and insidious,' but without a microscope it can be impossible to diagnose accurately in the initial stages. Before the 1820s, the history of kala azar is obscure. Garcia da Orta, a Portuguese physician and botanist who published Coloquios dos simples e drogas he cousas medicinais da India at Goa in 1563, described a case of fever that he cured by dosing the patient with ginger conserve and root of China in cinnamon water. Orta diagnosed a disease of the lymphatic system associated with "swellings on the liver and excrescences, and I was convinced that it was lymphatic, accompanied by some arid melancholy".2 Sir Harold Scott suggested that Orta might have described kala azar,3 although the disease has not been recorded in the area of Goa.