Fortunately, it appears Gretchen may have been treated for Lyme Disease before it became Chronic Lyme....
"Fox and Friends" Gretchen Carlson wasn't on vacation for the two weeks she was gone, she was battling Lyme Disease."
"While this hasn't made mainstream headlines, she did mention it in passing on "Fox and Friends" live.
http://www.examiner.com/article/fox-and-friend-s-gretchen-carlson-recently-battled-lyme-disease