Pregnant women should consider not travelling to the 2016 Olympic Games in Brazil due to the risk of Zika virus infection, the US Centers for Disease Control and Prevention says.
The CDC also said women considering becoming pregnant, and their male partners, should exercise caution if they travel to the Olympics or Paralympic Games, scheduled to take place in Rio de Janeiro in August and September.
"CDC recommends that pregnant women consider not travelling to the Olympics," the advisory says. "If you have a male partner who goes to the Olympics, you may be at risk for sexual transmission."
CDC's statement is the agency's first explicit warning for some travellers to stay away from the Games in Rio de Janeiro, which has been expecting to draw up to 400,000 tourists from around the world.
Although the Olympics are still five months away, Brazilian authorities have been drawing up robust mosquito-control plans to minimise the risks to spectators and tourists.
Much remains unknown about Zika, including whether the virus causes microcephaly in babies, a condition defined by unusually small heads that can result in developmental problems.
Brazil said it had confirmed more than 580 cases of microcephaly, and considers most of them to be related to Zika infections in the mothers. Brazil is investigating an additional 4100 suspected cases of microcephaly.
Though Zika is usually transmitted by mosquitoes, women who are pregnant may also be at risk for sexual transmission and should use condoms or refrain from sex during pregnancy if they are concerned, CDC said.
Those considering becoming pregnant should talk to their healthcare providers before travelling to the Olympics, the agency said.
A growing number of international athletes in recent weeks have said they are concerned about Zika, though few have said it would deter them from competing. Among those who have expressed reluctance is US soccer goalkeeper Hope Solo, who said Thursday she may not join her teammates in Brazil due to concerns about Zika.
The CDC's recommendations for travel to the Olympics are in line with its current guidance to travellers considering a trip to the countries where Zika is present.
Organisers have said transmission risks should be low during the Olympics, which are scheduled to take place during Brazil's winter months when transmission of mosquito-borne illnesses is less frequent and the weather is cooler and drier.
