I thought it was obvious... 2016 Summer Olympic games are being held in Brazil, the epicenter of the Zika virus pandemic. Aedes aegypti (a mosquito) is the disease vector. Tourists traveling to Brazil for the olympics will be at risk on contracting the disease and returning home. There are no known treatments or vaccines. The CDC has already issued warnings against traveling to these locations.<p>Aedes aegypti seems to be spreading in the US, with recent sightings in Sounthern and Central California -- not to mention natural populations in the South. So yeah, it could be really bad.