Tracking the public health effects of the Rio Olympics: HealthMap

Olympics Brazil Zika Health Map
Athletes around the world are converging on Brazil. What effects will this have on Zika and public health generally? (Nuno Lopes/Pixabay)

This past week, the 2016 Summer Olympic and Paralympic Games began in Rio de Janeiro, Brazil, with more than 11,000 athletes and 500,000 international fans expected to arrive. As a major mass gathering, the Olympic Games are always vulnerable to disease outbreaks. This summer, all eyes in public health are on the concurrently occurring Zika virus and the under-reported H1N1 influenza outbreak in Brazil.

According to the European Centre for Disease Prevention and Control (ECDC), visitors to the 2016 Games are most at risk for gastrointestinal illness from waterborne pathogens and mosquito-borne infections, including dengue, chikungunya and Zika virus. So far in 2016, we have seen an estimated 165,000 cases of Zika virus, 1,345,286 cases of dengue, 137,808 cases of chikungunya and more than 6,500 cases of H1N1 influenza, with an additional 1,233 deaths from H1N1 — all in Brazil alone.

Increased travel to Brazil brings a higher potential for these infectious diseases to spread rapidly to other countries when Olympic athletes and fans return to their home countries. To track ongoing and emerging outbreaks that may result from the Rio Olympics, HealthMap has created a surveillance map (

The map below (click to enlarge) displays any and all disease alerts related to the Olympics, focusing on new and ongoing infectious disease outbreaks, as well as alerts that may signify the potential emergence of a new outbreak. Users can customize their search by disease, location, source, species and date to match their view to their specific interest or need. Rio is flagged with a star.

Health Map Olympics screen grab updatedThe shaded pink areas denote countries sending the most athletes to Brazil (actual numbers appear inside the large dots — 242 for the U.S., for example). The green dots represent areas expected to receive post-Olympic travelers in August and September from major airports in Brazil (the smaller green dots indicate 500 or fewer people).

Overlaid on the map are Zika and dengue “suitability” maps for Africa and Asia. The orange areas are those where environmental conditions are suitable for Zika transmission by the Aedes aegypti mosquito; the blue areas are amenable to Zika transmission by Aedes albopictus. Finally, the un-numbered orange, red and purple dots indicate local disease activity (better appreciated on the live map, where removing the green dots will reveal them).

HealthMap’s surveillance will take place throughout the Olympic Games (August 5-21, 2016) and throughout the Paralympic Games (September 7-18) and continue after the sporting events come to an end. It should enhance our understanding of the spread of infectious disease from these events. With the potential for new diseases to be introduced to Brazil and for exportation of cases to new countries, the public health impact of the Games will be interesting to watch over the coming weeks.

Kara Sewalk MPH Health MapKara Sewalk, MPH, is a program coordinator at HealthMap, in Boston Children’s Hospital’s Computational Epidemiology Lab, and the Innovation and Digital Health Accelerator (IDHA).