Direction Sao Paulo and Rio de Janeiro. Brazil's two most populous cities have announced measures to deal with the explosion of dengue cases in the run-up to Carnival, which attracts millions of tourists from around the world. Dengue is now considered a re-emerging disease. Between 2000 and 2019, the number of cases reported globally increased from 500,000 to 5.2 million. Julia Sieger's explanations.