Reigning Commonwealth 100m champion Kemar Bailey-Cole claims he has been diagnosed with the Zika virus.
The Jamaican, 24, says he only learned of his condition after his girlfriend found a bump on his neck.
"I didn't know I had the virus and I have been training with it for three days now," he told the Jamaica Gleaner.
Fears over Zika, which is linked to serious birth defects, have led to several golfers, including Rory McIlroy, withdrawing from Rio 2016.
The mosquito-borne virus has been declared a global public health emergency by the World Health Organization (WHO), although the body has said there is no need to move or postpone the Games.
The outbreak began in Brazil a year ago, but now more than 60 countries and territories have been affected.
Bailey-Cole, who also won Olympic 4x100m gold alongside Usain Bolt at London 2012, said his girlfriend noticed the bump on his neck after he had a haircut.
"I was experiencing back pains and muscle soreness, but I thought it was just soreness from the exercises I was doing," the sprinter said.
"Recovering is not easy. The rashes are still on my body, my eyes hurt, but the best thing is that I am not feeling any muscle pain at the moment."
The discovery comes as Bailey-Cole is preparing for next week's Jamaican Olympic trials, where he will face the likes of Bolt, Asafa Powell and Yohan Blake for a place in Rio.
"[I am] going to trials with the mindset that I am healthy and ready," he added.