Impact of temperatures on malaria incidence in vulnerable regions of Pakistan: empirical evidence and future projections.

Abstract

Malaria presents a significant health challenge in developing countries, especially as climate change exacerbates its impact. Temperatures directly affect malaria transmission by influencing the abundance of disease vectors and the development of the malaria parasite. Pakistan, known for its warm, arid, and subtropical climate and frequent flooding, faces increased risks, emphasising the need for research to understand how heat affects malaria transmission. This study aims to provide empirical evidence of the relationship between temperature and malaria cases in two remote but highly vulnerable districts: Bannu and Lakki Marwat, with the goal of informing interventions to combat the negative effects of climate 38 change on malaria transmission in Pakistan. The monthly confirmed malaria cases and environmental factors (temperature, precipitation, and humidity) were analysed using a time-series study design with distributed lag nonlinear models and quasi-Poisson regression models. Malaria datasets acquired from the Integrated Vector Control/Malaria Control Program in Khyber Pakhtunkhwa were combined with publicly available gridded meteorological data from Copernicus ERA5-Land, covering the period from 2014 to 2022.The findings suggest that as temperatures exceed 22.4degreeC, malaria transmission increases by 9 to 10% for every 1degreeC rise in both districts. In Bannu, up to 39.8% 46 of reported malaria cases could be attributed to heat, while in Lakki Marwat, 54.1% of cases were attributable to heat. Projections based on Shared Socio-Economic Pathways forecast an increase in heat-related malaria cases by 0.8 to 3.5% in both districts under high emission scenarios by 2060s. The relationship between temperature and malaria transmission is complex and is influenced by multiple factors, including human behaviour and environmental conditions such as precipitation and humidity. Conducting empirical studies in highly vulnerable regions like Pakistan is crucial due to the inadequate healthcare infrastructure and limited resources, which heighten the vulnerability of populations to the impact of climate change. This study highlights the pressing need for implementing climate change mitigation and adaptation measures. This urgency is underscored by recent events in Pakistan, such as severe floods followed by a significant increase in malaria cases. Allocating resources to strengthen healthcare systems and enhance community resilience is especially critical in light of the recent challenges.Copyright © The Author(s), 2025. Published by Cambridge University Press.