The same warnings were issued in the late 1980's in Texas but the medical community was slow in accepting them. I remember circa 1990 telling a medical student about Chagas' disease in East Texas - she adamantly objected "No, we don't have that in Texas or North America for that matter. Chagas' is endemic to South America." I gently suggested that perhaps her textbooks were out of date and pointed out a report on a local childrens' hospital where Chagas' was not uncommon. Sounds like they still haven't updated the textbooks BTW.

These diseases are largely been brought in by human immigrants, i.e., it's not so much infected _bugs_ that are coming North as infected _humans_. Once here, the diseases spread among the local population. This is another unintended consequence of modern immigration policy: you get the cooties along with the people. Once upon a time, long ago, people with seriously infectious diseases were not allowed into the U.S.