( Stegomyia) albopictus mosquito vectors transmit the disease. In dengue-endemic countries, Aedes ( Stegomyia) aegypti and Ae. Worldwide, ≈14,000–20,000 dengue-related deaths occur each year ( 1, 2). Currently, ≈390 million new infections occur annually in 128 dengue-endemic countries ( 2). Global incidence of dengue has increased 7-fold, from 8.3 million cases in 1990 to >58.4 million in 2013 ( 1). The lessons learned from this outbreak are useful for other tropical nations facing increasing dengue incidence. Direct government expenditures on dengue control activities in 2017 were US $12.7 million. Changes in vector abundance were not predictive of the increased incidence. One quarter of total annual cases were reported 5 weeks after the southwest monsoon started. Limited virologic surveillance showed the dominant circulating variant was dengue virus type 2 cosmopolitan genotype in the most affected district. Older schoolchildren and young adults were more clinically symptomatic than those at extremes of age.
In all Sri Lanka districts, dengue incidence in 2017 increased significantly over incidence during the previous 5 years.
We conducted a comprehensive analysis of this epidemic by comparing national surveillance data for 2017 with data from the preceding 5 years. A total of 186,101 suspected cases and 440 dengue-related deaths occurred. In 2017, a dengue epidemic of unexpected magnitude occurred in Sri Lanka.
