Ultrastructural Development of Leishmania Chagasi in its Vector, Lutzomyia Longipalpis (Diptera: Psychodidae)

Infecção natural de Lutzomyia longipalpis por Leishmania sp. em Teresina, Piauí, Brasil

“…As demais amostras positivas apresentaram ambas as formas nas regiões do piloro, íleo e papila retal, ou seja, porções do trato digestivo posterior. Os resultados obtidos neste estudo são discordantes de outros que relataram a presença de formas procíclicas na porção anterior do estômago e nectomonadas no estômago, cárdia e válvula do esôfago 5,6 .…”

“…Realizou-se dissecação de, em média, dez fêmeas por captura. O trato digestivo e a cabeça foram retirados e observados para verificar a presença de formas evolutivas de Leishmania, segundo nomenclatura utilizada por Walters et al 5 e Sacks & Kamhawi 6 . A taxonomia dos insetos foi realizada de acordo com seus caracteres morfológicos 7 .…”

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

“…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. longipalpis as divi ding forms.…”

“…The sequence of events in the division of L. i. infantum in P. ariasi and L. i. chagasi in Lu. longi palpis (both natural pairs of parasite and vector) is (i) the production of a daughter flagellum, (ii) division of the nucleus into two, (iii) division of the kinetoplast into two and (iv) separation into two individuals by longitudinal fis sion beginning at the anterior end (Molyneux and KillickKendrick, 1987;Walters et al, 1989b).…”

“…With one exception, all accounts of the ultrastructure of leishmaniae in sandflies have shown attachment of pro mastigotes to the microvilli of the abdominal midgut by the insertion of the flagella of the parasites (Killick-Kendrick et al, 1974;Kaddu & Mutinga, 1981;Molyneux et al, 1986;Lawyer et al, 1987;Walters et al, 1987Walters et al, , 1989b. The excep tion is the only report, referred to above, on the ultra structure of a species of Viannia, L. panamensis, in the midgut of a sandfly by Walters et al (1989a) who sug gested that, because the parasites moved quickly from the hindgut to the anterior of the thoracic midgut, they perhaps had no « need to stabilize themselves in the midgut by association with the microvilli ».…”