Species diversity and spatial distribution of CL/VL vectors: evidence for variation in gene expression of immunogenic SP15 and LeIF proteins due to bioclimatic characteristics and physiological status of sand flies, Iran

Abstract Background Main approaches of this investigation were climate regionalization to recognize the spatial distribution of cutaneous/visceral leishmaniasis (CL/VL) vectors as risk-maps using ArcGIS modeling system, evaluation of species biodiversity, assessing bio-climate (BC) effect on expression plasticity of genes possessing vaccine properties isolated from wild-collected sand flies.Methods The Inverse Distance Weighting (IDW) interpolation method was used to obtain accurate geography map using ArcGIS10.3.1 in closely-related distances. Species diversity was calculated based on Shannon diversity index using Rv.3.5.3. Expression fold change of SP15 and LeIF genes was evaluated using cDNA synthesis and RT-qPCR analysis. Results Three BC zone were identified in northeast of Iran. Phlebotomus papatasi were abundantly captured in all BC regions and the frequency was more in plains areas of mountainous BC as hot spots of CL. VL vectors were more prevalent in spatial cluster of Mediterranean BC. Semi-arid BC was identified as a major contributing factor to up-regulate SP15 salivary gene expression ( P =0.0050, P <0.05), and Mediterranean BC had considerable effect on up-regulation of LeIF- Leishmania gene in gravid and semi-gravid P. papatasi population ( P =0.0109, P <0.05). Conclusions The diversity and spatial distribution of CL/VL vectors associated with BC regionalization obtained in our research provide epidemiological risk maps and establish more effectively control measures against leishmaniasis. Oscillations in gene expression indicate that each gene has its own features, which are profoundly affected by bioclimatic characteristics and physiological status of sand flies. It is essential to consider BC factors affecting regulatory regions of environmentally responsive loci for genes used in vaccine designing.