Top scientists now warn that the health risks of this summer's Olympic Games in Rio de Janeiro are so great, they should either be delayed or moved to another country. In an open letter to the World Health Organization, more than 100 of the world's leading scientists say the games suggested a relocation or postponement due to fears about the Zika virus's spread throughout the region. Despite the concern, however, the International Olympic Committee said earlier this week that it sees no reason to alter the current course. Zika is transmitted either sexually or from mosquitoes, causing birth defects for newborn babies. "An unnecessary risk is posed when 500,000 foreign tourists from all countries attend the Games, potentially acquire that strain, and return home to places where it can become endemic," the scientists wrote.