This January 2016 image provided by the Centers for Disease Control and Prevention (CDC) shows a Zika virus, a mosquito-borne disease that has been linked in Brazil to a large number of cases of microcephaly, a rare birth defect. Infants with microcephaly have smaller than normal heads and their brains do not develop properly. (Cynthia Goldsmith/CDC via AP)

Zika virus outbreak under close watch

The WHO declared the Zika virus an international health emergency. 22News explains what the virus is and where the outbreak is headed.