The role of promastigote secretory gel in the origin and transmission of the infective stage of Leishmania mexicana by the sandfly Lutzomyia longipalpis

Rogers, Matthew E., Chance, M and Bates, Paul (2002) 'The role of promastigote secretory gel in the origin and transmission of the infective stage of Leishmania mexicana by the sandfly Lutzomyia longipalpis'. Parasitology, Vol 124, Issue 5, pp. 495-507.

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Abstract

Transmission of leishmaniasis is effected by a specific developmental stage, the metacyclic promastigote. The precursors of metacyclic promastigotes were a distinct subpopulation of parasites, identified for the first time as a new stage in the life-cycle and named leptomonad promastigotes. Microdissection of infected sandflies into 4 midgut regions and foregut allowed precursor-product relationships to be established for amastigote-procyclic promastigote, procyclic-nectomonad promastigote, nectomonad-leptomonad promastigote and leptomonad-metacyclic promastigote, developmental switches. Metacyclic promastigotes occurred mainly in the thoracic midgut and cardia, coincident with the accumulation of a promastigote secretory gel (PSG) plug in these anterior regions. The gel-like plug was isolated from flies with mature infections and found to contain predominantly leptomonad promastigotes. The PSG plug also contained the majority (75%) of the total metacyclic promastigote population in the sandflies, which were concentrated at the anterior pole, The PSG plug was found to be the main site of metacyclogenesis, and acted as a reservoir of leptomonad promastigotes from which metacyclic forms differentiated and migrated for-ward to promote the infective potential of the fly. The PSG plug occluded and distorted the midgut, forcing the stomodeal valve open and affecting the feeding success of the sandflies, such that they experienced difficulty in taking a full meal. Collectively, these data support the role of the PSG in the transmission of leishmaniasis, by conditioning the midgut environment for metacyclogenesis and altering the feeding ability of infected sandflies.

Item Type:	Article
Subjects:	QX Parasitology > Insects. Other Parasites > QX 505 Diptera QX Parasitology > Protozoa > QX 70 Mastigophora. (e.g., Giardia. Trichomonas. Trypanosoma. Leishmania) WA Public Health > Preventive Medicine > WA 110 Prevention and control of communicable diseases. Transmission of infectious diseases WR Dermatology > Parasitic Skin Diseases > WR 350 Tropical diseases of the skin. Mucocutaneous leishmaniasis. Leishmaniasis
Faculty: Department:	Groups (2002 - 2012) > Molecular & Biochemical Parasitology Group
Digital Object Identifer (DOI):	https://doi.org/10.1017/s0031182002001439
Depositing User:	Lynn Roberts-Maloney
Date Deposited:	29 May 2013 10:41
Last Modified:	17 Aug 2022 08:56
URI:	https://archive.lstmed.ac.uk/id/eprint/2980

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