Perhaps the lesser known of the infectious disease of Southasia, and the most neglected, is Kala-azar. The name stands for "Black Sickness," because of the darkened colour assumed by the skin of some patients. Kala-azar is the Mogul period vernacular name of visceral Leishmaniasis, a disease fatal if not treated, that annually affects 500,000 people in 69 countries and has a population at risk of 350 million people. 90 percent of cases occur in Bangladesh, India, Nepal and Sudan.
Cause, symptoms, and distribution
The leishmaniasis are different illnesses caused by infection with a parasite called a protozoan, a single-celled organism considered to be the most simple in the animal kingdom. There are three forms of leishmaniasis – the cutaneous, the muco cutaneous and the third form that affects several organs and is called visceral leishmaniasis or Kala-azar. The last form of this disease is the one prevalent in India and Nepal.
The symptoms of Kala-azar include highly undulating fever, weight loss, fatigue, abdominal pain, cough and diarrhoea. Among the clinical signs are a dark colour of the skin, and enlargement of the spleen, liver and lymph nodes.
Kala-azar is normally present in areas of drought, famine and densely populated villages with poor or no sanitation and is not uniformly distributed in the affected areas. Among those most commonly affected are older children and young adults of both sexes with male preponderance. As a result of migration patterns, in recent years foci of Kala-azar are also present in cities where the poor live in densely populated ghettos in sub-standard conditions.