The Midgut Ultrastructure of the Sand Fly Vector, Phlebotomus Langeroni (Diptera: Psychodidae)

Abstract

The midgut ultrastructure of Phlebotomus langeroni, the vector of visceral leismaniasis was studied by the transmission electron microscope. The midgut region warrants a special investigation since it is directly relevant to the development of Leishmania promastigotes. Observations performed on females at time-intervals following a bloodmeal were analyzed and compared. The epithelium of the midgut consisted of a single layer of columner cells surrounded by the basal lamina. Under which there is a musculature consisted of circular and longitudinal fibers. The cells were characterized by large nuclei, densely packed microvilli, and intricate basal labyrinth. The cytoplasm was filled with numerous mitochondria. Morphological changes occurred in the cellular structures during the blood digestion process. The peritrophic matrix was present up to 3 days after the bloodmeal and completely disintegrated at day 4 after bloodmeal. At day 6 after bloodmeal, lipid inclusions were few within the cell cytoplasm and vacuoles were depicted. At day 8, the area of the microvilli was greatly reduced probably due to reduced functional activity along with the end of the digestive cycle. The changes depicted in the midgut of P. langeroni during the process of blood digestion were comparable to those described for other hematophagous dipterans.