leishmaniasis

Any of several parasitic diseases caused by microscopic protozoans of the genus Leishmania and transmitted by sandflies. It occurs in two main forms: visceral (also called kala-azar), in which various internal organs are affected, and cutaneous, where the disease is apparent mainly in the skin. Leishmaniasis occurs in the Mediterranean region, Africa, Asia, and Central and South America. There are 1.5–2 million new cases of leishmaniasis annually (as of 2006), with a total of 12 million people affected at any given time. The disease kills approximately 8,000 people a year in South America and results in hundreds of thousands more suffering permanent disfigurement and disability through skin lesions, joint pain, and swelling of the liver and spleen. The disease was identified by William Leishman (1865–1926).

In 1994 Indian researchers discovered a cheap and effective way of keeping sandfly populations under control, by plastering the walls of houses and outbuildings with mud and lime. The plaster deprives flies of the moist crevices in which they breed, and the lime kills any existing larvae. In trials, sandfly numbers dropped by 90%.

UK researchers determined the structure of the sex pheromone of the male sandfly, enabling Japanese researchers to synthesize the pheromone in 1999. This opened the way for possible control of sandfly numbers by attracting sandflies to areas of extermination rather than having to spray pesticides widely in urban areas, with all the concomitant risks.

In 2002, leishmaniasis reached epidemic levels in Afghanistan, prompting the World Health Organization (WHO) to call for more funding and research to fight the disease. In the early 2000s, leishmania/HIV co-infection emerged as a serious new disease and became increasingly frequent in southwest Europe, Brazil, and Africa.