WASHINGTON, July 13 (Xinhua) -- The U.S. Centers for Disease Control and Prevention (CDC) on Wednesday downplayed concern that the Rio Olympics will help spread the Zika virus worldwide, saying that the upcoming Games only posed "unique risk" to four small countries.
In a risk analysis report, the CDC said the risk of Zika virus transmission during the 2016 Olympic and Paralympic Games in Rio de Janeiro will be low because August and September are winter months in Brazil, when cooler and drier weather typically reduces mosquito populations.
The estimated 350,000 to 500,000 international visitors and athletes from about 200 countries who are expected to travel to Rio de Janeiro for the Games represent a tiny fraction -- less than 0.25 percent -- of the total travel volume to Zika-affected countries in 2015, said the CDC.
"Even if the Olympics didn't exist, 99.75 percent of global risk would be the same," CDC Director Tom Frieden told an event in New America, a Washington, D.C.-based think tank. "There is not a public health reason to delay or change the Games."
The CDC risk assessment identified 19 countries currently not reporting Zika outbreaks but with environmental conditions and population susceptibility that could sustain the virus if a traveler returned home infected from the Games.
But for 15 of them, travel to Rio de Janeiro during the Games is not estimated to increase substantially the risk of importing Zika because they already have substantial travel to Zika-affected countries.
The remaining four countries, Chad, Djibouti, Eritrea and Yemen, which are expected to send 19 athletes and a delegation of 60 people to Rio, could "have a problem," said Frieden.
That's because the four countries do not have substantial travel to any country with local Zika virus transmission, except for their participation in the Games.
Overall, "with the exception of four countries, attendance at the Games does not pose a unique or substantive risk for mosquito-borne transmission of Zika virus in excess of that posed by non-Games travel," said the CDC report.
Meanwhile, the CDC continued to advise all pregnant women to avoid traveling to any areas where Zika virus transmission is ongoing, including Rio de Janeiro.
"Athletes and visitors to Rio de Janeiro and other Zika transmission areas should follow precautions to prevent exposure to the virus," the CDC report wrote. "Specifically, all delegation members and visitors should take rigorous steps to reduce the likelihood of mosquito bites both during the Games and within the three weeks after they return to their home country." Enditem