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RISK ANALYSIS AND EARLY ACTION SELECTION
Prioritized hazard and its historical impact
Dengue is considered the most rapidly spreading mosquito-borne disease worldwide (WHO, 2009). In Sri Lanka, the first reported cases appeared in 1965, and the disease quickly escalated into an island-wide epidemic. Between 1965 and 1968, with 51 suspected cases and 15 deaths were reported. From 1969 to 1988, several similar outbreaks occurred, predominantly in urban areas, although case reporting during this period was sporadic.
According to the Weekly Epidemiological Report (Sri Lanka, 2008), dengue became a recurring public health issue with increasing frequency and severity beginning in 1989. Significant outbreaks were recorded in the early 2000s, notably in 2002 and 2004, with 8,931 and 15,463 reported cases, respectively. The most severe outbreak occurred in 2017, with 186,101 cases and a case fatality rate of 0.24%. Based on data from the National Dengue Control Unit (NDCU), this remains the highest number of reported cases in the past decade.
Figure 1 in the PDF presents the number of suspected dengue cases and the case fatality rate in Sri Lanka from 2001 to 2024. A notable surge occurred in 2019, with cases doubling from 51,659 in 2018 to 105,049, with an increase in deaths. During the COVID-19 pandemic period (2020–2021), dengue cases remained relatively controlled. In 2022, the number of reported cases rose to 76,689, although this figure remained below the 2019 peak. According to the National Dengue Control Unit (NDCU), 89,799 suspected dengue cases were reported in 2023, marking a significant increase compared to 2022.
Dengue prevention requires coordinated efforts from the government, private sector, and communities. In Sri Lanka, the government and public health authorities have implemented various measures to control and prevent dengue outbreaks. These include vector control initiatives such as identifying and eliminating mosquito breeding sites, conducting case investigations, implementing educational campaigns, and promoting public awareness. However, achieving optimal outcomes has been hindered by several challenges, including limited resources, inconsistent implementation of preventive strategies, and insufficient community engagement.
The Sri Lanka Red Cross Society (SLRCS) successfully implemented two DREF operations (MDRLK007 in 2017 and MDRLK017 in 2023) in response to dengue outbreaks. These interventions contributed significantly to controlling the spread of the disease. Notably, the early launch of the 2023 operation helped prevent the number of cases from reaching the epidemic levels seen in 2017, highlighting the importance and effectiveness of early action.
These operations also provided the Sri Lanka Red Cross Society (SLRCS) with valuable experience in dengue prevention and complemented the efforts of national health authorities. Consequently, it is essential to monitor meteorological and environmental factors that influence mosquito breeding—such as temperature, rainfall, and humidity—and to develop early warning and early action systems specifically tailored to mitigate dengue outbreaks.