Climate Change and Spatiotemporal Distribution of Major Vector-Borne Diseases in South Asia: A Systematic Review

Abstract

Abstract 
Background: South Asia is among the most climate-vulnerable regions globally, experiencing rapid warming, altered 
precipitation patterns, and increased frequency of extreme weather events. These changes have important 
implications for vector-borne diseases (VBDs), which remain a major public health burden in the region. 
Objective: This systematic review synthesizes evidence on the relationship between climate change and the 
spatiotemporal distribution of major vector-borne diseases in restricted South Asia (India, Pakistan, 
Bangladesh, Sri Lanka, Nepal, and Bhutan), focusing on malaria, dengue, chikungunya, Japanese 
encephalitis, and visceral leishmaniasis. 
Methods: A systematic literature search was conducted in PubMed, Web of Science, Google Scholar, and relevant 
government and WHO reports for studies published up to December 2023. The review followed PRISMA 
guidelines. Studies assessing climatic trends, spatial or temporal distribution of vectors and diseases, or 
associations between climatic variables and disease transmission were included.  
Results: A total of 24 studies were included in the qualitative synthesis, consistent with the PRISMA flow diagram. 
Evidence indicates a regional warming trend, increasing temperature extremes, and changing rainfall 
patterns across South Asia. These climatic changes are associated with altitudinal and latitudinal expansion 
of malaria, dengue, chikungunya, Japanese encephalitis, and visceral leishmaniasis into previously non
endemic areas, including highland and peri-urban regions. Temperature and rainfall were the most 
consistently reported climatic drivers, although non-climatic factors such as urbanization, population 
mobility, land-use change, and vector control interventions strongly modified observed patterns. 
Conclusion: Climate change is contributing to the changing spatiotemporal distribution of major VBDs in South Asia, 
particularly through expansion into new ecological zones. Integrated surveillance, climate-informed early 
warning systems, and regionally coordinated public health strategies are urgently needed to mitigate future 
risks.