Biological targeting and drug delivery in control of Leishmaniasis

Leishmaniasis is a neglected tropical disease caused by a protozoan parasite of the genus Leishmania. Visceral leishmaniasis is the most severe type and is transmitted by the phlebotomine sandflies of genera Lutzomyia (New World) or Phlebotomus (Old World) to human and other vertebrates. Leishmaniasis is widespread in developing countries with current mortality rate of 50 thousand deaths per year. The parasites adopt different biochemical approaches to evade the host immune system. Knowledge in chemical control of leishmaniasis is currently emerging and not many drugs are available. Control of parasite is complex and WHO has put an ardent appeal for development of drugs and delivery devices against leishmaniasis. Main-stay in treatment of leishmaniasis is pentavalent antimonials but second-line drugs like amphotericin B and pentamidine are available. Clinical acceptability of drugs is poor due to severe toxicity, poor bioavailability, improper localization and recent appearance of resistant variants. Interest in leishmanicidal chemotherapy is therefore renewed and biochemical strategies or improved delivery appear to be a solution. Trends in control of leishmaniasis also include specific applications of low-cost, locally available plant drugs in different delivery devices. This work attempts to present a comprehensive overview of the different approaches to targeted leishmanicidal chemotherapy.