I am a nurse, TADA.... Lol, but the reason I say this is I am a nurse instructor... I tell all my students the same thing about mosquitos, bed bugs, lice, etc. They do not have to have passports, they know no borders, they don't know the difference between North Miami and Lake Buena Vista.
If you are pregnant it would absolutely behoove you to check with your doctor, read the CDC guidelines/warnings, and follow their advice. If you do choose to travel use whatever products that are safe to protect yourself and your unborn child.
There is great advice here from Previous Posters, but I would absolutely rely on my Doctor's advice....
Good luck, and remember WDW us not going away anytime soon, there's always next year!