Here’s some practical advice from NPR on how to avoid mosquito bites. DEET works, and has been more or less proven safe. So, somewhat surprisingly, does eucalyptus oil.
I am fairly careful about mosquitoes, and yet I have been bitten by them in Florida, Thailand, Singapore, Indonesia and less exotic places on the U.S. eastern seaboard. So far I haven’t caught West Nile, St. Louis, dengue, chikungunya, Japanese encephalitis, and had never even heard of Zika until last month although it is supposedly common in places I have been. Then again, I could have an asymptomatic infection with one or more of these, who knows. If you talk to enough people from tropical countries, the majority have had dengue at some point, usually with a full recovery. But it can cause a particularly cruel and grizzly death in a few unlucky cases.
None of this is to make light of the horrible complications we are seeing with Zika. It’s just that like anything, your best bet is to take reasonable precautions and try to be as rational about the likelihood and consequences of unfamiliar risks as a human can.