Unlike stable transmission settings in Africa the drivers of focal, heterogeneous infection and disease risks among the arid areas of Africa remain poorly defined. The populations in North West and North Eastern Kenya are poor, semi-nomadic groups with little acquired functional immunity to P. falciparum, marginalized by the 2001-09 national malaria strategy as they were assumed to be at no risk. Risks however, appear to be very focal concentrated in areas of seasonal water which also determines where people live. A more detailed empirical investigation of malaria risk, including susceptibility to P.