Why Zika Is Totally Out of Control In Puerto Rico

Puerto Rico is experiencing an explosion of cases of the Zika virus, something U.S. health officials have feared for some time.

In a recent study, the U.S. Centers for Disease Control and Prevention (CDC) reported that 5,582 people in Puerto Rico have tested positive for Zika, which is thought to be a gross underestimate since most people who get the virus don't show symptoms.