The federal Centers for Disease Control and Prevention report nearly 600 travel-associated cases of Zika virus in the United States, as of May 25.

Three of those were in Arizona; New York and Florida had the most cases.

A University of Arizona researcher is part of a team looking into which American cities could be at high risk for Zika.

Kacey Ernst is an associate professor in epidemiology in the College of Public Health at UA. Ernst talked about how to define which are high-risk areas.