Abstract:
Dengue fever is a major global and local public health concern, primarily transmitted by Aedes
aegypti and Aedes albopictus mosquitoes. As a tropical country, Sri Lanka is currently
experiencing significant impacts from the disease. The simultaneous circulation of all four viral
serotypes (DENV-1, 2, 3, and 4) since 2000 has resulted in a hyperendemic situation in the
country in recent years. The Western Province has consistently been a hotspot for Dengue
outbreaks over the past decade. This study aims to analyze the spatial and temporal patterns
of Dengue cases reported in the Western Province from 2013 to 2023 using Geo spatial
analyses. Weekly Dengue data from Medical Officer of Health (MOH) divisions were used in
this descriptive study. In this study, time series and regression analyses were conducted to
examine the temporal distribution of Dengue cases, while spatial patterns and regional risk
areas were identified using Moran’s I spatial autocorrelation analysis and hotspot mapping
techniques in ArcMap 10.8. Trend analysis was also carried out to recognize the future trend
of Dengue cases at the district level. Findings revealed significant variation in both temporal
and spatial distribution of Dengue cases. Colombo District reported the highest number of
cases, with a consistent pattern of higher incidence in urban areas across all three districts
Colombo, Gampaha, and Kalutara. Moran’s I and Hotspot analysis revealed a clustered case
distribution, especially in areas marked by unplanned urban development, high population
density, and poor waste management. Time series analysis indicated both positive and negative
reporting trends in Colombo and Kalutara MOH divisions. However, it is noteworthy that all
MOH divisions in the Gampaha District demonstrated exclusively positive trends in timely
case reporting. Trend-based projections further suggest the emergence of future hotspots,
particularly in expanding semi- urban regions. The findings underscore the need for targeted
vector control measures, urban planning reforms, and sustained public health interventions to
mitigate the effects of virus transmission in Western Province.
