Ultrastructural Biology of Leishmania (Viannia) Panamensis (=Leishmania Braziliensis Panamensis) in Lutzomyia gomezi (Diptera: Psychodidae): A Natural Host-Parasite Association

The life-cycle ofLeishmaniain the sandfly with special reference to the form infective to the vertebrate host

“…Unlike paramastigotes of other species in the foregut of the sandfly, the hindgut forms of L. braziliensis were commonly in division and attachment, by hemidesmosomes, was at any part of the flagellum, not only the tip. Similar studies by Walters et al (1989a) on another species of the Neotropical subgenus Viannia Lainson and Shaw, 1987, L. panamensis, in Lu. gomezi, a sandfly assumed to be a natural vector (see Killick-Kendrick, 1990), showed that the predominant form attached to the intima of the hindgut was not a paramasti gote, but a « spatulate-shaped promastigote ».…”

“…An equally plausible interpretation is that a parasite or a flagellum had been cut across a fold and a similar interpretation is possible with electronmicrographs of paramastigotes of L. panamensis in the foregut of Lu. gomezi believed by Walters et al (1989a) also to be in division.…”

“…They defined nectomonads as long, slender, electron-dense unattached promastigotes and haptomonads as broad, electron-lucid promastigotes with modified fla gella capable of producing electron-dense plaques (hemidesmosomes) inside the sheath, associated with attachment to the cuticular intima of the stomodaeal valve. The same terms have been used for similar forms seen in other infec tions Lawyer et al, 1987;Walters et al, 1987Walters et al, , 1989a. The definitions of nectomonads and haptomonads were challenged by Walters et al (1989a) who preferred them simply to denote either free-swimming or attached promastigotes with no consideration of morpho logy.…”

“…The same terms have been used for similar forms seen in other infec tions Lawyer et al, 1987;Walters et al, 1987Walters et al, , 1989a. The definitions of nectomonads and haptomonads were challenged by Walters et al (1989a) who preferred them simply to denote either free-swimming or attached promastigotes with no consideration of morpho logy. A separation into nectomonads and haptomonads was not seen in preliminary observations on the ultrastructure of L. i. infantum in P. ariasi (Killick-Kendrick et al, 1977c).…”

“…Its shape is oval or round and it is much less motile than the promastigote. Like haptomo nads on the stomodaeal valve, paramastigotes attach to the cuticular intima of the foregut of the fly by the tip of the flagellum within which hemidesmosomes are formed (Killick-Kendrick et al, 1977a, 1988Walters, 1989a, b)). Whereas Killick-Kendrick (1979) believed paramastigotes in the foregut did not divide, Walters et al (1989b) inter preted their electronmicrographs of some paramastigotes of L. i. chagasi in the foregut of Lu.…”