Kenya’s counties and populated malaria risk margins: 47 counties shown as dark lines with the extents of major rivers and lakes (light blue); areas unable to support Plasmodium falciparum transmission (dark grey) and low population density (light grey). Turkana (1), West Pokot (2), Trans Nzoia (3), Bungoma (4), Busia (5), Kakamega (6), Siaya (7), Kisumu (8), Homa Bay (9), Migori (10), Kisii (11), Narok (12), Bomet (13), Nyamira (14), Kericho (15), Vihiga (16), Nandi (17), Uasin Gishu (18), Elgeyo Marakwet (19), Baringo (20), Nakuru (21), Nyandarua (22), Laikipia (23), Nyeri (24), Murang’a (25), Kiambu (26), Nairobi (27), Kajiado (28), Makueni (29), Machakos (30), Embu (31), Kirinyaga (32), Tharaka Nithi (33), Meru (34), Samburu (35), Isiolo (36), Marsabit (37), Mandera (38), Wajir (39), Garissa (40), Lamu (41), Tana River (42), Kitui (43), Taita Taveta (44), Kwale (45), Kilifi (46), Mombasa (47). To establish the likely margins of malaria transmission, a temperature suitability index (TSI) has been used based on the monthly average land surface temperatures, the average survival of Anopheles mosquitoes and the length of sporogony that must be completed within the lifetime of one Anopheline generation, where 0 represents the inability to support transmission (dark grey) [14]. Kenya’s population is unevenly distributed within its national borders, with large areas of its land mass characterized by unpopulated areas represented by large conservation areas and deserts. Areas where population density is less than 1 person per km2 (light grey) [11] (Fig. 1)  were excluded from subsequent malaria risk extraction