Leishmania vaccines: old and new.

The approach to the development of a Leishmania vaccine has undergone a revolution since its early beginnings with the ancient practice of leishmazation: the inoculation of infectious parasites from an active lesion in order to produce a self-healing lesion in a healthy individual. Controlled infection has been followed by injection of killed parasites and has now progressed to subunit and naked DNA vaccines. Emanuela Handman here discusses the current studies and the future prospects for a Leishmania vaccine with a focus on cutaneous leishmaniasis. Unfortunately, what J.F. Williams said about antiparasite vaccines in 1987 (Ref. 1) is still true in 1997: 'the reasons for optimism are less evident than the reasons for enthusiasm'.