The United States Olympic Committee is to recruit two infectious disease experts to advise potential members of their Rio 2016 Games team who are concerned about the Zika virus outbreak in Brazil.
"I know the Zika virus outbreak in Brazil is of concern to many of you," wrote USOC CEO Scott Blackmun in a letter sent to prospective Olympians."
"I want to emphasise that it is to us, as well, and that your well-being in Rio this summer is our highest priority.
"We have been in close contact with the US Centers for Disease Control and Prevention (CDC) as well as infectious disease specialists with expertise regarding the Zika virus."
Brazil is the worst-hit country in the outbreak of Zika that is sweeping the Americas.
"We are learning more every day," wrote Blackmun in his letter. "We continue to closely monitor the situation through the CDC."
"No matter how much we prepare, however, there will always be risk associated with international competition."
The Zika virus, until recently viewed as relatively mild, has sparked concern because of a possible link between infection in pregnancy and microcephaly, a rare birth defect in which infants are born with abnormally small heads that can be accompanied by developmental problems.
Brazil is investigating a potential link between Zika infections and more than 4,000 suspected cases of microcephaly.
Researchers have identified evidence of Zika infection in 17 of these cases, either in the baby or in the mother, but have not confirmed that the virus can cause microcephaly.