I certainly do understand wanting to avoid even the most miniscule of risks.
But just FYI re: Brazil---
There have been 120 total cases of Zika in Rio de Janeiro, the whole state, not just the city. Most of the cases have been in the far northeast of Brazil. There is no proven connection between Zika and birth defects (as yet).
And a little personal perspective:
In over 20 years of regular long term travel to Brazil, all over the country and in all sorts of neighborhoods, I have not gotten dengue, ever. The same mosquito carries Zika.