Dengue and the World Football Cup: A Matter of Timing

The possibility of a dengue fever outbreak during the FIFA Football World Cup raised controversies about the use of health data and the impact of climate on dengue dynamics. One example of this debate is the article “Football fever could be a dose of dengue” recently published in Nature by Simon Hay and its repercussion in media and scientific forums. The risk map presented by Hay appears to be from a previously published global dengue risk assessment, but zoomed into the Brazilian territory. It is important to distinguish between downscale and zoom. The environmental spatial covariates used to produce the map may be relevant for the global perspective, but in Brazil, other spatiotemporal variables influence transmission intensity and permanence. For instance, dengue vectors are well adapted to urban and peri-urban environments and infest even dry regions. However, small, cold, and remote cities are virtually preserved from prolonged transmission. We provide a nationwide risk map, averaging June dengue incidence rates for 2001–2012. The areas along the Amazonian rivers and in the inner portions of southernmost states are actually low-risk areas, while elevated dengue risk is found in the central Brazilian plateau. During austral summer, high incidence is observed in all central regions, while in winter, transmission is restricted to narrow areas along the northern coast and central regions. Among the cities where football games will take place, Porto Alegre, Curitiba, and São Paulo are located in year-round low-transmission areas. During the winter, only Fortaleza, Natal, Recife, Salvador (along the northeast coast), and Cuiabá remain in active, albeit low, transmission areas. The difference between these maps relates to the consideration of seasonality, timing, and scale.