Dengue incidence and associated costs in the periods before (2000-2008) and after (2009-2013) the construction of the hydroelectric power plants in Rondônia, Brazil.

Objective: to describe the incidence of dengue cases and associated costs in the period before and after the construction of the Jirau and Santo Antônio hydroelectric power plants (HPP), in Rondônia State, Brazil.

Methods: economic evaluation study, based on data from the Notifiable Diseases Information System (SINAN) and the National Hospital Information System (SIH/SUS); dengue direct costs were calculated and segmented regression analysis was carried out.

Results: dengue incidence mean was higher in the period after HPP construction (880.29/100,000 inhabitants) than before them (356.34/100,000 inhabitants) (p≤0.05); direct costs were estimated at US$3.47 million in the pre-construction period and US$7.1 million in the post-construction period.

Conclusion: there was an increase in the incidence and direct costs of dengue after HPP construction; the environmental licensing process should include more detailed health impact assessments.