Laboratory demonstration of the acquisition and development of leishmania major in the sand fly Phlebotomus kazeruni (Diptera: Psychodidae).

ABSTRACT

Phlebotumus kazeruni, a blood-feeding, xerophilic sand fly species found broadly throughout North Africa and Western Asia, is a suspected vector of cutaneous leishmaniasis (CL). Following successful laboratory colonization of this species, we employed the murine (BALB/c) infection model to determine whether our Sinai strain of P. kazeruni was able to successfully acquire, develop, and transmit a Sinai strain of Leishmania major. Groups of female sand flies were fed 1) by membrane, hamster blood containing culture-produced L. major promastigotes, 2) by membrane, hamster blood containing a suspension of L. major tissue amastigotes, and 3) directly upon L. major lesions in BALB/c mice. Samples of blood-fed sand flies from each group were dissected on selected days post-feeding and examined by light microscope for acquired and developing Leishmania infections. Female P. kazeruni acquired viable parasites by the three feeding methods. Development of ingested parasites to infective-stage metacyclic forms was observed and seen to progress from midgut to the mouthparts. Promastigote infection rates were 20% in flies fed directly upon infected mice, 35% in those fed amastigotes via membrane, and 100% in flies fed culture promastigotes via membrane. Direct blood fee-ding upon BALB/c mice was more avid (P < 0.001) among previously blood-fed flies, possibly indicative of selection and colony adaptation to murine blood-feeding. Although we failed to demonstrate clear transmission of infective-stage L. major promastigotes by feeding infected flies upon a susceptible murine host, and producing lesions in the animal, the progressive development of L. major from amastigote to metacyclic-stage promastigotes, and movement of the parasites from sand fly midgut to its mouthparts, provides evidence that P. kazeruni could serve as a vector for this parasite.