Leishmaniasis vaccine candidates for development: a global overview.

A vaccine against different forms of leishmaniasis should be feasible considering the wealth of information on genetics and biology of the parasite, clinical and experimental immunology of leishmaniasis, and the availability of vaccines that can protect experimental animals against challenge with different Leishmania species. However, there is no vaccine against any form of leishmaniasis for general human use. One major factor is the lack of a conceived market for human leishmaniasis vaccines. Hence pharmaceutical industries involved in vaccine development are not interested in investing millions of dollars and a decade that is required for developing a new vaccine. Besides, leishmaniasis is a local/regional problem and not a global one. According to the estimates of the World Health Organization, 90 per cent of visceral leishmaniasis occurs in five countries (Bangladesh, Brazil, India, Nepal and Sudan). Those in need are amongst the poorest people in these countries. It should therefore be the objectives of these countries to develop a vaccine. Fortunately, both Brazil and India have designated the control of visceral leishmaniasis as a top priority for their respective Ministries of Health. The purpose of this review is to present only the vaccines in use and those in development for use in dogs or humans. This is not an exhaustive review of vaccine discovery or the principles of clinical immunology underlying vaccine development.