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Transmission of Leishmania metacyclic promastigotes by phlebotomine sand flies

Paul A Bates1

  • 1Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK. pbates@liverpool.ac.uk

International Journal for Parasitology
|May 23, 2007
PubMed

Insights

Leishmania parasites transmit through sand fly bites, primarily via a blocked fly mechanism. This involves regurgitation of promastigote secretory gel (PSG) and infective parasites into the host.

Area of Science:

  • Vector-borne diseases
  • Parasitology
  • Infectious disease transmission

Background:

  • Understanding infectious agent transmission is key for effective interventions.
  • Leishmania parasites are transmitted by sand flies.

Purpose of the Study:

  • To review the mechanisms of Leishmania transmission by sand fly vectors.
  • To explore factors influencing parasite transmission efficiency.

Main Methods:

  • Review of existing literature on Leishmania transmission.
  • Analysis of parasite-host interactions within the sand fly vector.

Main Results:

  • The primary transmission mechanism involves a "blocked fly" state caused by promastigote secretory gel (PSG) secretion.
  • Sand flies regurgitate PSG and metacyclic promastigotes into mammalian hosts during feeding.
  • Other potential factors include stomodeal valve damage, salivary gland parasite presence, and anal excretion.

Conclusions:

  • The blocked fly mechanism is the most significant route for Leishmania transmission.
  • Variations in transmission mechanisms exist across Leishmania subgenera (Leishmania, Viannia, Sauroleishmania).
  • Further research into these mechanisms can inform control strategies.

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