I think you missed the point.
Yes, people who are traveling to Rio should take precautions against mosquito bites, the same as when you visit an area where malaria is present. And pregnant women should avoid Brazil altogether due to the risk to the fetus.
But what the doctors' petition warned of - and what the WHO has called "bullshit" on - is the idea that people traveling to Rio for the Olympics will carry the virus back home with them and start a "Zika apocalypse" that will spread around the globe.
Here's what's wrong with that idea: like malaria, the Zika virus is carried by a particular species of mosquito. They're prevalent in parts of Africa (where Zika has always existed), the Caribbean, and the South Pacific. Not North America, Europe, or Asia.
While in Rio I'll be staying in Ipanema, a block and a half from the ocean. Mosquitoes don't like salt water so they aren't typically present at the beach. Many of the Olympic events I'll attend will be held indoors, so once again mosquitoes won't be an issue. When I attend an outdoor event at an inland location - track & field, for instance - I'll wear a DEET-based repellant. That worked well enough to prevent me from contracting malaria when I visited Malaysia, Thailand, New Guinea, Costa Rica...
In Southern California where I live there aren't any mosquitoes at all, so if I bring the virus home it won't matter to anybody but me. Of course it's also possible to transmit the virus through semen - but I'm a gay man; I already have precautionary measures in place to prevent sexual transmission of viruses.