The spatial and temporal distribution, species composition, and host preference of phlebotomine sand flies in the Bethlehem District of Palestine

Abstract

In the Palestinian West Bank, leishmaniasis is emerging as a serious public health issue with incidence increasing over time, especially in the western and the northern parts. This study was aimed to evaluating the effect of altitude on sand fly density, temporal and spatial distribution, species composition, and host preference within and between three villages in the Bethlehem District. The three villages occur along an elevation cline, ranging from the disease-free area of Kisan (KIS; 732–782 m ASL), down to the endemic areas of Arab Ar-Rashaiyda (AAR; 522–568 m ASL), and Al‘Azazma (AZA; 473–510 m ASL) in the Bethlehem District (southeastern West Bank). Sand flies were trapped monthly from May through October in 2013 in traps located north, south, east, and west of each village. The abundance of sand flies differed among the three villages, with Arab Ar-Rashaiyda (AAR) > Al ‘Azazma (AZA) >Kisan (KIS). The sex ratio was even in AAR and AZA, and female biased in KIS. Both male and female Phlebotomus sand fly densities varied with elevation, with greatest densities found at intermediate elevations (AAR). Elevation correlated negatively with the proportion of blood-fed Phlebotomus females. Male Phlebotomus species composition differed among sites, with all the species found in this study present in AZA, while some species were absent from AAR and KIS. The host blood species engorged by P. sergenti were grouped in four categories: human (45.5%), livestock (25%), avian (19.9%), and dog (9.6%). This study provided information about the spatial and temporal distribution, age and species composition, and host preference of sand fly vectors that influence disease transmission. This information will allow us to better target sand flies, to control the disease, and to monitor risk prone areas.