In south Asia, where kala azar is believed to be prevalent in only 96 districts, WHO says the disease can definitely be eradicated if we make sure there are no infected humans and no sandfly carriers. This would require early diagnosis, an effective cure and successful vector control.

The sandfly which is the vector for kala azar, breeds in and around homes, in thatched roofs, cracks and crevices of mud used to plaster walls, in cow dung, and in the shrubs and low greenery around homes. With the WHO having re-endorsed indoor residual spraying of DDT by application on walls and roofs of houses in September 2006, it will help the vector control programme.

We need to keep in mind, however, that the vector control programme for malaria in India, with heavy reliance on indoor residual spraying and inadequate use of other interventions, led to an increase in cases of malaria and an increase in resistance to DDT. In the case of kala azar too, development of tolerance by the sandfly to DDT has been reported from several districts. Thus, operational coverage with accurate spraying techniques and the correct insecticide will be key to a successful vector control programme.

Currently used drugs for kala azar show variable efficacy and are toxic. They also involve a treatment course of about four to six weeks, which creates its own problems. We need shorter therapies as four week treatments are difficult to support given the high incidence of the disease and the overstretched health infrastructure in the regions where the disease is endemic. Long treatments specially lead to low compliance and consequent drug resistance.

... contd.