Zika virus is a disease that has caused thousands of newborn babies to have underdeveloped brains, according to BBC News. The virus is carried through Aedes mosquitos through the Americas, except for Chile in Canada where it is too cold for them to survive. It can also be transmitted sexually.
The cause for concern with the upcoming Olympics is due to the widespread growth in Brazil, the host country of the 2016 Summer Olympics.
In 2014, Brazil had less than 150 cases of microcephaly, which is a baby being born with an abnormally small head and a major symptom of zika virus.