With the Olympic games scheduled for later this year in Brazil, athletes and national Olympic committees across the globe are expressing concern about the Zika virus, which is spread by mosquitoes. 
 
 George Boville, an Olympic bronze medalist swimmer for Trinidad and Tobago in the 200 meter individual medley and two-time world champion, told ABC News that he was worried about going to Brazil, where the outbreak of the Zika virus in the Americas started. 
 
 "It is definitely a concern," he told ABC News via Twitter. By the time of the Olympic games, "it should be rampant." 
 
 The New Zealand Olympic Committee and the Australian Olympic Team Committee have already told their athletes to take protective measures. 
 
 The New Zealand Olympic Committee said they are abiding by government recommendations, which at this point advise "expectant mothers or those planning pregnancy do not travel to areas with the Zika virus present." 
 
 "We would support any athlete or support staff member in their decision to not attend the games if this were the case," the committee said in a statement last week. 
 
 The Australian Olympic Committee said they are advising all athletes to wear long sleeves and that any team member who is "pregnant at the time of the Games need to consider the risks very carefully before deciding whether to proceed with travel to Brazil." 
 
 American wrestler Adeline Grey told reporters at a test event on Sunday at Rio's Olympic Park that she didn't plan to skip the games, but that if she were pregnant she would reconsider participating. 
 
 "If I was planning to have a child next month, I would be extremely uneasy about this," Gray said, according to the Associated Press. "Maybe that would have changed my decision" to come to Rio for the test event. 
 
 The International Olympic Committee released a note on Friday to all Olympic committees outlining medical advice. 
 
 "We remain confident that there will be a safe environment for successful and enjoyable Olympic Games in Rio de Janeiro," the IOC said in the statement. 
 
 The United States Olympic Committee officials said they are most concerned about the well-being of athletes and staff going to the games. 
 
 "We continue to closely monitor the situation through the CDC and have ongoing contact with the International Olympic Committee, the organizing officials in Rio, the World Health Organization and infectious disease specialists with expertise in tropical diseases, including the Zika virus," the USOC said in a statement. 
 
 The Zika virus is characterized by mostly mild symptoms, including fever, rash and fatigue. However, it has been associated with a worrying rise in a dangerous birth defect called microcephaly, where an infant is born with an abnormally small head. It has been known to be associated with developmental delays and seizures. 
 
 Rio 2016's communications director, Mario Andrada, said there currently was no measurable reaction in ticket-holders, according to Reuters. 
 
 "Tickets have not been returned nor trips canceled," he said, according to Reuters. 
 
 Pregnant Olympic athletes are a rare occurrence, but multiple women have reportedly competed while they were unknowingly pregnant. At the 2012 Summer Olympics, Kerri Walsh Jennings was five weeks pregnant when she won the gold medal, according to ESPN.com. 
 
 And many of those who travel to the Olympics are the family members of the athletes. ||||| NEW YORK (Reuters) - The United States Olympic Committee told U.S. sports federations that athletes and staff concerned for their health over the Zika virus should consider not going to the Rio 2016 Olympic Games in August. 
 
 The logos of the Rio 2016 Olympic Games and Rio 2016 Paralympic Games are pictured next to a message on a screen that reads "Message about Zika" during a media briefing in Rio de Janeiro, Brazil, February 2, 2016. REUTERS/Ricardo Moraes 
 
 The message was delivered in a conference call involving USOC officials and leaders of U.S. sport federations in late January, according to two people who participated in the call. 
 
 Federations were told that no one should go to Brazil “if they don’t feel comfortable going. Bottom line,” said Donald Anthony, president and board chairman of USA Fencing. 
 
 The USOC’s briefing to sport federations is the latest sign that Olympics officials are taking the Zika threat to the games in Rio de Janeiro seriously, and acknowledging that at least some athletes and support staff could face a tough decision over whether to attend. 
 
 The United States won most medals at the last Olympics in London in 2012, so any disruption to its presence would be important for the Rio games. 
 
 Global health authorities suspect the mosquito-borne Zika virus has caused a spike in Brazil of microcephaly, a birth defect marked by an abnormally small head. As a result, the World Health Organization declared an international health emergency Feb. 1, and the U.S. Centers for Disease Control and Prevention (CDC) is advising pregnant women or those considering becoming pregnant to avoid travel to places with Zika outbreaks. 
 
 The USOC’s Alan Ashley, its chief of sport performance, and other USOC officials, briefed the leaders of the federations. 
 
 Ashley did not respond to email or phone calls requesting comment. 
 
 USOC spokesman Mark Jones confirmed by email that Ashley had “briefed federation leaders on the CDC’s recommendations and we will continue to ensure that athletes and officials affiliated with Team USA receive any updates from the CDC.” 
 
 The USOC has not issued its own set of recommendations for athletes and staff beyond what the CDC and WHO have issued. 
 
 Jones declined to comment further or respond to specific questions from Reuters before publication. 
 
 In a statement on Monday, another USOC spokesman Patrick Sandusky said media reports that the USOC has advised U.S. athletes to reconsider competing in Rio due to the Zika virus were inaccurate. It was unclear what media reports he was referring to and he couldn’t be immediately reached for comment. 
 
 “Team USA looks forward to the Games and we did not, would not and will not prevent athletes from competing for their country should they qualify,” Sandusky said. 
 
 EXPRESSED OPTIMISM 
 
 Recalling the conference call, Anthony, a former Olympian, said: “One of the things that they immediately said was, especially for women that may be pregnant or even thinking of getting pregnant, that whether you are scheduled to go to Rio or no, that you shouldn’t go.” 
 
 “And no one should go if they feel at all as though that that threat could impact them,” said Anthony, who praised the USOC’s handling of the outbreak so far. 
 
 Zika outbreaks have been reported in 33 countries, most of them in the Americas. Symptoms of infection often are mild or imperceptible. But the outbreak in Brazil that began last year has been accompanied by more than 4,000 cases of suspected microcephaly; investigators have confirmed more than 400. The link to Zika is unproven but strongly suspected. 
 
 Related Coverage Factbox: Impact of Zika virus on Olympic preparations 
 
 In El Salvador, which is experiencing outbreaks of the virus, women are being advised to put off pregnancy until 2018. 
 
 Will Connell, Director of Sport at the U.S. Equestrian Federation, said the USOC was leaving the decision up to individual athletes and staff members. 
 
 “They said no one who has reasons to be concerned should feel obliged to go,” Connell said. “If an athlete feels that way, of course they may decide not to go.” 
 
 During the call, the USOC did not indicate they were concerned that large numbers of athletes would avoid Rio or that Zika could derail the Games, the two federation leaders said. 
 
 Instead, officials expressed optimism that risk would be minimized by close cooperation among health agencies, mosquito control efforts and the Games’ timing during Brazil’s winter when mosquito-borne illnesses are less common. 
 
 The USOC officials on the call said the organization would adhere to the recommendations of health agencies including the CDC, the sport federation leaders said. 
 
 “As we get closer to the Olympics the guidance could get updated,” Connell said. 
 
 In a Jan. 29 letter from the International Olympic Committee (IOC) to national committees, the IOC’s chief doctors said they were monitoring the situation closely. They passed along mosquito avoidance advice, but remained confident the games would go ahead as planned. 
 
 The Australian and New Zealand Olympic Committees said they had already warned their athletes of the potential dangers for pregnant women. 
 
 “If any athletes on the team felt they didn’t want to go, we would absolutely support them on that,” an NZOC spokeswoman said on Tuesday. 
 
 An Australian Olympic Committee spokeswoman said they would “totally understand” if an athlete chose not to go to Brazil. 
 
 “But at this point no athletes have indicated they intend to withdraw from the team,” she added. 
 
 Both Connell and U.S. Fencing’s Anthony said the USOC’s message was focused primarily on the potential risks for women who are pregnant or are thinking about trying to become pregnant. 
 
 Since the call, the CDC has issued more guidance in light of increasing suspicion that Zika can be transmitted sexually. The CDC said Friday that men who reside in or have traveled to Zika-affected areas may want to abstain from sexual activity or use condoms. 
 
 The Olympics have long promised to be a triumphant showcase for Latin America, which is playing host to the global sports spectacle for the first time. Rio has also been expecting more than 380,000 tourists for the Games, which come as Brazil’s economy is mired in recession and its government reels from a corruption scandal at state oil company Petrobras. 
 
 An ongoing Zika epidemic could prompt some athletes, staff, sponsors and high-spending tourists to steer clear of the Games. Even if the risk of infection to any given visitor is very low – as health experts expect – uncertainties persist. There is no Zika vaccine, and currently available blood tests cannot always detect the virus. 
 
 Olympics officials “are taking the right approach from a standpoint of, let’s be cautious, do not do anything that is going to put anybody, our staff or our athletes in danger,” Anthony said. 
 
 Anthony said no U.S. fencers had spoken to him about Zika. 
 
 “I think our athletes are aware,” he said. “But it has not become a mission critical issue yet. Not yet.”
– If the US medal count is lower than normal at the Summer Olympics this year, blame mosquitoes. The United States Olympic Committee has spread the word to American athletes: If the Zika virus worries them, they should skip the Games in Brazil, reports Reuters. The message came in a conference call to the leaders of US sports federations, and the head of USA Fencing says that the "bottom line" was clear enough: Nobody should head to Rio "if they don't feel comfortable going." ABC News previously rounded up concerns of US athletes, including wrestler Adeline Grey saying she might have opted out of a recent competition in Rio had she been pregnant.