Sri Lanka is currently grappling with a dual health crisis: the resurgence of chikungunya after 16 years and a persistent dengue epidemic(Urbanisation). Both diseases, transmitted by Aedes mosquitoes, have reached epidemic levels in 2025, particularly affecting urban and suburban regions like Colombo, Gampaha, and Kandy .
This blog post explores how rapid urbanisation has influenced the spread of these vector-borne diseases, examining the interplay between urban growth, environmental factors, and public health challenges.
Urbanisation and Its Role in Disease Spread
Urbanisation in Sri Lanka has led to increased population density, inadequate housing, and strained infrastructure. These conditions create ideal breeding grounds for Aedes mosquitoes. Poor waste management and water storage practices in urban areas provide stagnant water sources, facilitating mosquito proliferation.
Furthermore, urban expansion often outpaces the development of essential services, leading to environments where vector control is challenging. The concentration of people in cities also means that once an infection is introduced, it can spread rapidly through the population.
Environmental Factors Amplifying the Epidemics
Sri Lanka’s tropical climate, characterized by high humidity and consistent temperatures, supports year-round mosquito breeding. Monsoon rains exacerbate the situation by creating additional breeding sites through water accumulation in both natural and artificial containers .
Climate change further complicates control efforts. Rising temperatures and altered rainfall patterns can expand the geographic range of mosquitoes, introducing diseases to previously unaffected areas.
The Re-emergence of Chikungunya
After a 16-year hiatus, chikungunya has re-emerged in Sri Lanka, with cases reported in multiple districts. Genomic studies indicate that the current outbreak is caused by the Indian Ocean lineage of the virus, similar to strains circulating in South Asia .
The resurgence is partly attributed to urbanisation-related factors, including increased human mobility and inadequate vector control in densely populated areas.
Public Health Challenges and Responses
The simultaneous outbreaks of dengue and chikungunya strain Sri Lanka’s healthcare system. Hospitals face increased patient loads, and distinguishing between the two diseases can be difficult due to overlapping symptoms.
Public health responses focus on vector control, public education, and surveillance. Efforts include community clean-up campaigns to eliminate breeding sites, dissemination of information on preventive measures, and monitoring of disease spread to implement timely interventions.
Conclusion
Urbanisation in Sri Lanka has significantly impacted the spread of dengue and chikungunya. Addressing these epidemics requires integrated approaches that consider urban planning, environmental management, and robust public health strategies. Sustainable urban development, coupled with effective disease surveillance and community engagement, is essential to mitigate the impact of these vector-borne diseases.
