Mississippi detected positive in a few scattered counties between Memphis and Vicksburg about the same time (not including the hot zone border counties). I believe that testing in subsequent years has not found additional positives. Similar scenario — 50 - 100 miles from next closest positives. Makes you think vultures must be a vector for spreading the prions on the landscape. It's been a couple of years since I read about those, but I believe Mississippi was performing a second confirmation test.
I had my first positive in Haywood County in November and received a call from TWRA biologist last week. She said they are using the ELISA test, and only running a second confirmation test if it is located in a new county.