Expression plasticity of Phlebotomus papatasi salivary gland genes in distinct ecotopes through the sand fly season.

BACKGROUND: Sand fly saliva can drive the outcome of Leishmania infection in animal models, and salivary components have been postulated as vaccine candidates against leishmaniasis. In the sand fly Phlebotomus papatasi, natural sugar-sources modulate the activity of proteins involved in meal digestion, and possibly influence vectorial capacity. However, only a handful of studies have assessed the variability of salivary components in sand flies, focusing on the effects of environmental factors in natural habitats. In order to better understand such interactions, we compared the expression profiles of nine P. papatasi salivary gland genes of specimens inhabiting different ecological habitats in Egypt and Jordan and throughout the sand fly season in each habitat. RESULTS: The majority of investigated genes were up-regulated in specimens from Swaymeh late in the season, when the availability of sugar sources is reduced due to water deprivation. On the other hand, these genes were not up-regulated in specimens collected from Aswan, an irrigated area less susceptible to drought effects. CONCLUSION: Expression plasticity of genes involved with vectorial capacity in disease vectors may play an important epidemiological role in the establishment of diseases in natural habitats.

Discovery of diurnal resting sites of phlebotomine sand flies in a village in southern Egypt.

In an attempt to find diurnal resting sites of adult phlebotomine sand flies, potential phlebotomine adult habitats were aspirated in the village of Bahrif in Aswan, Egypt. During this survey, sand flies were aspirated from low (30-45 cm high) irregular piles of mud bricks found under high date palm canopies between the village and the Nile River. There were 5 males and 7 females of Phlebotomus papatasi and 3 males of Sergentomyia schwetzi. Six of the 7 aspirated females were engorged with blood. A total of 78 sand flies was captured on 3 glue boards placed overnight on the ground next to the mud bricks. Attempts to aspirate sand flies from adjacent walls and plants were unsuccessful. The identification of diurnal resting sites in less structured habitats may ultimately lead to more effective adult sand fly control.