CLIMATE CHANGE AND DENGUE FEVER OUTBREAKS IN THE TWIN CITIES OF PAKISTAN: A 13-YEAR EPIDEMIOLOGICAL AND METEOROLOGICAL ANALYSIS (2013–2025)

Abstract

Background: Dengue fever has emerged as a critical public health concern in Pakistan, with the twin cities of Rawalpindi and Islamabad (ICT) representing two of the most severely affected urban centers in South Asia.  

Objective: This study investigates the association between climatic variables - specifically ambient temperature and precipitation - and dengue fever incidence over a 13-year period (2013–2025) in these geographically contiguous cities.

Methods: Monthly dengue case reports were compiled from National Institute of Health (NIH) Pakistan, Pakistan Red Crescent Society (PRCS), and district health records for Islamabad Capital Territory (ICT) and Rawalpindi district. Meteorological data - daily maximum and minimum temperatures, and monthly accumulated precipitation - were obtained from Pakistan Meteorological Department (PMD) weather stations at Islamabad (Nur Khan) and Rawalpindi (Chaklala). Pearson correlation coefficients and linear regression analyses were performed to quantify the climate–dengue relationship. Temporal lag effects were explored, and a seasonal heatmap analysis was conducted to identify within-year patterns.

Results: A statistically significant positive correlation was observed between annual mean maximum temperature and dengue incidence (r = 0.35, p < 0.05). Annual precipitation demonstrated a moderate positive association with dengue cases (r = 0.35 with a one-year lag), consistent with the hypothesis that monsoon flooding creates larval breeding habitats whose effects materialise in subsequent transmission seasons. Peak transmission was consistently observed in September–November (post-monsoon), with 2021 and 2022 representing catastrophic epidemic years (twin cities combined: ~11,061 and ~14,755 cases respectively). Mean annual maximum temperature in the twin cities increased by approximately 0.21°C per year between 2013 and 2025, representing a significant warming trend. Cases escalated from under 1,600 combined in 2013 to over 14,700 in 2022, a nearly 10-fold increase.

Conclusion: Climate change - manifesting as rising temperatures and increasingly variable precipitation patterns - is significantly associated with escalating dengue burdens in Pakistan's twin cities. The convergence of urban heat island effects, monsoon flooding, inadequate vector control infrastructure, and a warming climate creates a highly permissive environment for Aedes-borne dengue transmission. Evidence-based interventions integrating climate-informed early warning systems, enhanced vector surveillance, urban water management, and public health preparedness are urgently required to mitigate the projected further increase in dengue burden under continued climate change.