Occurrence of Leishmania major in sandfly urine

Promastigotes of Leishmania major were frequently detected in the urine droplets discharged by infected Phlebotomus papatasi and P. duboscqi females during feeding. Parasites were present in the urine of 37·5% P. papatasi and 16·1% P. duboscqi females, even in those with low intensity gut infections. Free-swimming forms (elongated nectomonads, short slender promastigotes and metacyclic forms) predominated in excreted droplets. Viability of excreted parasites was proved by cultivation on blood agar, and the presence of metacyclic forms in urine droplets was confirmed by specific fluorescence assay with 3F12 antibodies. While the release of promatigotes from the anus of the sandfly was frequent, these were rarely egested from the mouth-parts of sandfly females (1·3% for P. duboscqi and 0% for P. papatasi) fed on microcapillaries, even if the females were heavily infected. The possible role and significance of the discharge of parasites in sandfly urine are discussed.

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A novel role for the peritrophic matrix in protecting Leishmania from the hydrolytic activities of the sand fly midgut

Parasitology ◽

10.1017/s0031182097001510 ◽

1997 ◽

Vol 115 (4) ◽

pp. 359-369 ◽

Cited By ~ 99

Author(s):

P. F. P. PIMENTA ◽

G. B. MODI ◽

S. T. PEREIRA ◽

M. SHAHABUDDIN ◽

D. L. SACKS

Keyword(s):

Digestive Enzymes ◽

Leishmania Major ◽

Specific Inhibitor ◽

Sand Fly ◽

Peritrophic Matrix ◽

Phlebotomus Papatasi ◽

Hydrolytic Activities ◽

Natural Vector ◽

Parasite Survival

The role of the peritrophic matrix (PM) in the development of Leishmania major infections in a natural vector, Phlebotomus papatasi, was investigated by addition of exogenous chitinase to the bloodmeal, which completely blocked PM formation. Surprisingly, the absence of the PM was associated with the loss of midgut infections. The chitinase was not directly toxic to the parasite, nor were midgut infections lost due to premature expulsion of the bloodmeal. Most parasites were killed in chitinase-treated flies within the first 4 h after feeding. Substantial early killing was also observed in control flies, suggesting that the lack of PM exacerbates lethal conditions which normally exist in the blood-fed midgut. Early parasite mortality was reversed by soybean trypsin inhibitor. Allosamadin, a specific inhibitor of chitinase, led to a thickening of the PM, and also prevented the early parasite mortality seen in infected flies. Susceptibility to gut proteases was extremely high in transitional-stage parasites, while amastigotes and fully transformed promastigotes were relatively resistant. A novel role for the PM in promoting parasite survival is suggested, in which the PM creates a barrier to the rapid diffusion of digestive enzymes, and limits the exposure of parasites to these enzymes during the time when they are especially vulnerable to proteolytic damage.

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Human cellular and humoral immune responses to Phlebotomus papatasi salivary gland antigens in endemic areas differing in prevalence of Leishmania major infection

PLoS Neglected Tropical Diseases ◽

10.1371/journal.pntd.0005905 ◽

2017 ◽

Vol 11 (10) ◽

pp. e0005905 ◽

Cited By ~ 1

Author(s):

Wafa Kammoun-Rebai ◽

Narges Bahi-Jaber ◽

Ikbel Naouar ◽

Amine Toumi ◽

Afif Ben Salah ◽

...

Keyword(s):

Salivary Gland ◽

Immune Responses ◽

Leishmania Major ◽

Phlebotomus Papatasi ◽

Major Infection ◽

Humoral Immune ◽

Humoral Immune Responses ◽

Endemic Areas

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Phlebotomus papatasi Antimicrobial Peptides in Larvae and Females and a Gut-Specific Defensin Upregulated by Leishmania major Infection

Microorganisms ◽

10.3390/microorganisms9112307 ◽

2021 ◽

Vol 9 (11) ◽

pp. 2307

Author(s):

Barbora Kykalová ◽

Lucie Tichá ◽

Petr Volf ◽

Erich Loza Telleria

Keyword(s):

Gene Expression ◽

Antimicrobial Peptides ◽

Leishmania Major ◽

Larval Instar ◽

Gut Bacteria ◽

Sand Fly ◽

Control Group ◽

Phlebotomus Papatasi ◽

Major Infection ◽

Defensin Gene

Phlebotomus papatasi is the vector of Leishmania major, causing cutaneous leishmaniasis in the Old World. We investigated whether P. papatasi immunity genes were expressed toward L. major, commensal gut microbes, or a combination of both. We focused on sand fly transcription factors dorsal and relish and antimicrobial peptides (AMPs) attacin and defensin and assessed their relative gene expression by qPCR. Sand fly larvae were fed food with different bacterial loads. Relish and AMPs gene expressions were higher in L3 and early L4 larval instars, while bacteria 16S rRNA increased in late L4 larval instar, all fed rich-microbe food compared to the control group fed autoclaved food. Sand fly females were treated with an antibiotic cocktail to deplete gut bacteria and were experimentally infected by Leishmania. Compared to non-infected females, dorsal and defensin were upregulated at early and late infection stages, respectively. An earlier increase of defensin was observed in infected females when bacteria recolonized the gut after the removal of antibiotics. Interestingly, this defensin gene expression occurred specifically in midguts but not in other tissues of females and larvae. A gut-specific defensin gene upregulated by L. major infection, in combination with gut-bacteria, is a promising molecular target for parasite control strategies.

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