Antileishmanial Resistance – Reasons and Remedies

Visceral leishmaniasis (VL) or Kala-azar is the most severe form of leishmaniasis and is uniformly fatal, if untreated. An estimated 500,000 new cases occur per year, 90% of which occur in the endemic areas of India, Bangladesh, Sudan Nepal and Brazil. More than 100,000 cases of VL occur in India alone every year and the state of Bihar accounts for more than 90% of these. Over the years new therapies have developed for VL e.g. liposomal amphotericin B, oral miltefosine, and paramomycin. Although a number of drugs have now become available for the treatment of leishmaniasis; each have limitation of either toxicity, long course of treatment, need for hospitalization and close monitoring or parenteral administration (except miltefosine). At the same time as these new therapies are becoming available the standard pentavalent antimonials (Sb) are being threatened by development of resistance. It is therefore imperative to look into the reasons behind the development of resistance and prevent future resistance.