Is the world ready for the Zika virus?

The World Health Organization has declared the Zika virus and the suspected associated birth defects an international public health emergency. Experts say the numbers are a sign that global surveillance systems — important for medical response — are working. But with no vaccine available and only five laboratories that can diagnose the virus in the U.S., there is a long road ahead. In this America Tonight excerpt, Lisa Fletcher talks to public health experts about the global health disaster we're now facing.