DEVELOPMENT OF ENDOTRYPANUM (KINETOPLASTIDA, TRYPANOSOMATIDAE) IN EXPERIMENTALLY INFECTED PHLEBOTOMINE SAND FLIES (DIPTERA, PSYCHODIDAE)

The developmental biology (parasite establishment, migration, and diff erentiation) of Brazilian strains of Endotrypanum are reported for 3 s and fly species: Lutzomyia longipalpis Lutz & Neiva, L. shannoni Dyar, and Phlebotomus papatasi Scopoli. Laboratory- reared sand flies were infected by feeding on a promastigote suspension through a chick-skin membrane. Infections within the insect gut were examined at various ti mes after feeding by staining fresh and fixed specimens. Development o f Endotrypanum varied for each parasite-host species association. Afte r feeding on culture forms of E. schaudinni Mesnil & Brimont (strain I SHA/BR/80/IM1111), significantly more L. shannoni (100%, 9/9) became i nfected than did L. longipalpis (62.3%, 33/53) or P. papatasi (27.3%, 15/55). The greatest number of infections were in the midgut and hindg ut from 6 to 16 d after feeding, but flagellates also were present in the Malpighian tubules. Moreover, distinct development patterns in the sand fly gut were obtained when the Callejon L. longipalpis colony wa s fed on cultures of other Endotrypanum strains. Significantly fewer s and flies became infected with strain MCHO/BR/5/IM2259 (18.2%, 4/22) t han with strain ISHA/BR/80/IM1111 (55.6%, 20/36). There were also indi vidual variation in the distribution and survival of parasites within the guts of flies in each group. These data indicate that there is var iation in the susceptibility to infection with Endotrypanum among and within sand fly species.