Climate change and its association with the expansion of vectors and vector-borne diseases in the Hindu Kush Himalayan region: A systematic synthesis of the literature

Observed weather and projected climate change suggest increases in the transmission of vector-borne diseases (VBDs) in the Hindu Kush Himalayan (HKH) region. In this study, we systematically explore the literature for empiric associations between the climate variables and specific mosquito-borne diseases and their vectors in the Himalaya Hindukush region. We conducted a systematic synthesis of the published literature on weather variables and VBDs in the HKH region to 8th December 2020. The majority of studies show significant positive associations of vector-borne diseases with climatic factors such as temperature, precipitation, relative humidity, etc. This systematic review allowed us to identify the most significant variables to be considered for evidence-based trend estimates of the effects of climate change on VBDs and their vectors in HKH region and set this evidence in to the context of climate change trend and with the observed expansion of VBDs and disease vector in the HKH region. The geographic range of vector-borne diseases expanded into previously considered non-endemic areas of highlands (mountains) in the HKH region. Based on scarce, but clear evidence of positive relationship of most climate variables and VBDs and the trend of climatic changes, we strongly recommend an expansion of vector control and surveillance programmes in previously considered non-endemic areas of the HKH region.