This is a very good question, I also wonder about what people do that live in the lower elevation coastal regions, for yellow fever or dengue fever as well. Is there any issues with mosquito born diseases in these areas. Is DEET readily available or can some one comment about their experiences.
Also, it would be great if this forum had a search function, as this may have been covered already but going thorough all of the posts to find it is kind of time consuming. Just a thought.