Organizers of this year’s Olympics in Rio de Janeiro tried their best on Thursday to make the Zika virus seem not so scary after all.

In their final presentation to the International Olympic Committee’s executive board before the Games in August, the organizers said the virus would pose no health risk to athletes and visitors. They noted that the Games would take place during the Southern Hemisphere’s winter, when mosquito populations plummet. Because of that, a spokesman declared with confidence, the rate of infection from the Zika virus “drops to very low numbers, very near zero.”

With the Games only about 60 days away, the public relations push was expected. And maybe the final sales pitch will make a few more athletes and visitors feel safe.

But for at least one American athlete, it was too late.

About the same time the Olympic committee and its guests were putting away their charts, papers and laptops, the cyclist Tejay van Garderen was announcing that he had withdrawn from consideration for a place on the United States team. A top professional who has twice finished fifth in the Tour de France, van Garderen was a likely bet to make the squad in Rio. But he is skipping the Games, he said, because he is afraid of contracting the Zika virus and possibly transmitting it to his pregnant wife and their unborn daughter.