Leishmaniases are the third most pervasive insect-bone diseases (following Malaria and Dengue), affecting tropical as well as arid regions in under-developed countries. However, CL is a neglected disease and developing a more thorough understanding of its ecology is vital. We are using Old World Zoonotic Cutaneous Leishmaniasis (ZCL) as a model system to study this question. Leishmania major, the protozoan parasite that causes Old World ZCL, is transmitted by the sand fly Phlebotomus papatasi and maintained by Psammomys obesus (the fat sand rat) in native arid landscapes but recently was described to also be maintained by Meriones tristrami in agriculturally modified regions. In native arid regions, we have shown that anthropogenic disturbances, of various types, share the common effect of elevating soil moisture, which enhances sand fly and sand rat abundance and thereby amplifying pathogen transmission and spill-over rates of the infection into adjacent human populations (see, flow chart model below) (Wasserberg et al. 2002, 2003ab, Berger et al. 2014). However, a recent outbreak of Old World ZCL in a northern, mostly agricultural semi-arid region, is yet poorly understood. We are currently studying this system in order to better understand the ecological and, possibly, evolutionary processes underlying this emergence.