The mosquito-borne Zika virus has caused athletes to pull out of the Olympic Games and prompted countries to design special protective uniforms ahead of Rio 2016, says CNN.

British long jumper Greg Rutherford will be there, but he's taking no chances, with the defending Olympic champion freezing a sample of his sperm before heading to the Games as a precautionary measure against Zika.

Last month, a host of prominent doctors and professors penned an open letter to the World Health Organization (WHO) calling for the Games to be moved or postponed "in the name of public health."

Despite these concerns, Rio 2016 director of communications Mario Andrada said Tuesday organizers were "110% comfortable" they could protect everybody attending the Games.

The International Olympic Committee insists it has no plans to delay or cancel South America's first Olympics. The Center for Disease Control (CDC) recently confirmed Zika's link to microcephaly - a birth defect that results in an underdeveloped brain - and is studying its connection to other malformations.

So far there is no vaccination that can ward against the virus.

Brazilian officials have argued the risk of infection is seriously reduced during the Games, because they are being held in the South American winter month of August, when mosquito populations tend to die.

According to Rio's health secretariat, the number of Zika cases has already declined significantly. According to their figures, the city has seen a total of 26,576 cases of Zika so far this year, with a peak in February of 7,232 cases. In May, there were 702 reported cases.