Duke physician: Zika can present challenges to Olympians returning home

Before joining Team USA, 31-year-old tennis player Brian Baker was aware of the risks of Zika in Rio. Baker's brother, Art, is an infectious disease physician at Duke.

"His level of concern was actually pretty low, to be honest," Art Baker said of his brother.

While his younger brother could not turn down an opportunity to represent his country, Art Baker said he did talk to his brother about avoiding mosquitos.

"He and his teammates have not seen any mosquitos since they have been there," Baker said. "When they are outside playing their matches, or training, they are wearing insect repellant and being very careful about that."

Still, some Rio visitors may develop Zika virus symptoms, such as a high fever, rash and joint aches. Even some with no symptoms may still be infected, which, according to experts, presents two big challenges upon returning home.

"Number one, to avoid mosquito bites upon your return home for a period of several weeks," Baker said.

If domestic mosquitos bite an infected person, those mosquitos may then become new carrier of the virus. Baker said the second challenge is preventing sexual transmission that could lead to severe birth defects.

"Males who have had symptoms should avoid pregnancy with their partner for at least a 6-month period, but for those who don't have any symptoms, 8 weeks of avoiding pregnancy is really important," Baker said.