An outbreak of the Zika virus in the Americas has turned into a public health emergency, according to the World Health Organization. Though most cases of the virus are harmless, some health officials believe it may be linked to a sharp increase in birth defects. Scientists also think Zika infections can trigger a severe neurological disorder, called Guillain-Barré syndrome, in a small number of cases. As a result, health officials and researchers around the world are trying to figure out how the Zika virus works — and what can be done to prevent it. You can follow along here for the latest.