Sergentomyia schwetzi is not a competent vector for Leishmania donovani and other Leishmania species pathogenic to humans

Jovana Sadlova, Vit Dvorak*, Veronika Seblova, Alon Warburg, Jan Votypka, Petr Volf

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

57 Scopus citations

Abstract

Background: Sand fly species of the genus Sergentomyia are proven vectors of reptilian Leishmania that are non-pathogenic to humans. However, a consideration of the role of Sergentomyia spp. in the circulation of mammalian leishmaniasis appears repeatedly in the literature and the possibility of Leishmania transmission to humans remains unclear. Here we studied the susceptibility of colonized Sergentomyia schwetzi to Leishmania donovani and two other Leishmania species pathogenic to humans: L. infantum and L. major. Methods. Females of laboratory-reared S. schwetzi were infected by cultured Leishmania spp. by feeding through a chicken membrane, dissected at different time intervals post bloodmeal and examined by light microscopy for the abundance and location of infections. Results: All three Leishmania species produced heavy late stage infections in Lutzomyia longipalpis or Phlebotomus duboscqi sand flies used as positive controls. In contrast, none of them completed their developmental cycle in Sergentomyia females; Leishmania promastigotes developed within the bloodmeal enclosed by the peritrophic matrix (PM) but were defecated together with the blood remnants, failing to establish a midgut infection. In S. schwetzi, the PM persisted significantly longer than in L. longipalpis and it was degraded almost simultaneously with defecation. Therefore, Leishmania transformation from procyclic to long nectomonad forms was delayed and parasites did not attach to the midgut epithelium. Conclusions: Sergentomyia schwetzi is refractory to human Leishmania species and the data indicate that the crucial aspect of the refractoriness is the relative timing of defecation versus PM degradation.

Original languageAmerican English
Article number186
JournalParasites and Vectors
Volume6
Issue number1
DOIs
StatePublished - 2013

Bibliographical note

Funding Information:
We would like to thank to Prof. Asrat Hailu, Addis Ababa University, for kindly providing the L. donovani isolate. This study was supported by the Bill and Melinda Gates Foundation Global Health Program [grant number OPPGH5336], GACR 13–07 500S and EDENext 2011–261504, the paper is cataloged by the EDENext Steering Committee as EDENext 099.

Keywords

  • Peritrophic matrix
  • Phlebotomine sand flies
  • Phlebotomus
  • Sergentomyia
  • Visceral leishmaniasis

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