11. Integrated vector management for control, elimination and prevention-of-reintroduction of malaria in Sri Lanka: a historical review

A review of malaria vector control in Sri Lanka was conducted to understand how the country successfully transitioned from control of malaria to elimination over the past century, and how vector control is being used to prevent the reintroduction of malaria. The case study is expected to provide examples and lessons learnt to other programmes or countries. Malaria vector control in Sri Lanka has faced major challenges of sudden and unstable transmission, insecticide resistance, movements of settlers and refugees, and programme fatigue. Early on, the importance of vector ecology and environmental factors in malaria epidemics was recognised, and in response, vigilance units were set up at periphery level. After intense indoor residual spraying campaigns with DDT (1950s and 1960s) and, subsequently, malathion failed to end malaria (1970s), pesticide policy was developed in the 1980s, and a routine system of monitoring of insecticide resistance was incorporated into the malaria control programme. This system was the basis for a proactive scheme of rotation and mosaics of insecticide applications to manage resistance. Entomological and epidemiological surveillance data were used to stratify malaria incidence, identify high-risk groups or locations, and plan appropriate interventions, including larval vector control. The programme adapted to changing epidemiological circumstances. After Sri Lanka was certified malaria-free in 2016, the system of surveillance and control was reoriented, with malaria risk mapping providing the basis for decisions on proactive vector control in receptive and vulnerable locations. The vector control programme has been disease-specific, but in recent decades the entomological expertise has regularly been shared with the dengue control programme, which is an example of integrated vector management. Further coordination on vector surveillance and control between programmes will be vital to improve the efficiency, effectiveness and financial sustainability of operations.