According to ABC News:
Federal health officials today said they believe thousands of people may have contracted the Zika virus before returning to the U.S. and they remain concerned that the virus might commence ongoing transmission in the U.S.
Speaking at a panel at the Woodrow Wilson International Center for Scholars, Dr. Anne Schuchat, the principal deputy director at the Centers for Disease Control and Prevention, said the Zika virus remains “pretty concerning” for experts as they learn how it affects pregnant women.
“The reality is one bite, and if you’re pregnant, your baby might be harmed,” Schuchat said at the panel today. “That’s a phenomenal problem.”