Dryland salinity and vector-borne disease emergence in southwestern Australia

Broad-scale clearing of native vegetation for agriculture in southwestern Australia has resulted in severe ecosystem degradation, which has been compounded by the subsequent development of large areas of dryland salinity; decreased transevaporation allows the water table to rise, dissolving ancient aeolian salt deposits and creating saline surface pools. The mosquito-borne disease Ross River virus has been noted as a potential adverse human health outcome in salinity-affected regions because the principal vector, Aedes camptorhynchus, is salt tolerant and thrives preferentially in such systems. To understand the geology and ecology underlying the relationship between land clearing and disease emergence, we examine the relationship between dryland salinity processes that determine the dissolved solids profile of saline pools in affected areas, the mosquito vectors and interactions with the human population within the disease cycle. Aedes camptorhynchus is able to survive in a wide range of salinities in pools created by dryland salinity processes. The link with disease emergence is achieved where population distribution and activity overlaps with the convergence of environmental and ecological conditions that enhance disease transmission.