4 Reasons Disease Outbreaks are Erupting Around the World

MERS, H1N1, swine flu, chikungunya, Zika: Another virus with a peculiar name always seems to be right around the corner, threatening to become a pandemic.

Over the past decade, the World Health Organization has declared four global health emergencies. Two of them were in the past two years: the Ebola epidemic in West Africa and the Zika outbreak that's spread through the Americas.