Intravectorial cycle of Leishmania in sandflies.

The development of Leishmania spp. in their vectors is a complex process involving behavioural, morphological and biochemical changes. The process differs between Leishmania species. Recent information on the developmental process and its regulation, summarised in this report, relates to possible separation of amastigotes into two separate developmental lines, development of infective forms of promastigote, attachment of certain, possibly altruistic promastigotes to the gut wall, and the possibility of genetic exchange.