Zika outbreak: What you need to know

The World Health Organization has declared the Zika virus a global public health emergency.

What Is a Coma?

A coma is a prolonged state of unconsciousness. During a coma, a person is unresponsive to his or her environment. The person is alive and looks like he or she is sleeping. However, unlike in a deep sleep, the person cannot be awakened by any stimulation, including pain.