It started with a horsefly bite. Or, at least, that’s what doctors think. Steve Wilson didn’t have a cut when he cast his first line in the Gulf off the coast of Mississippi on Saturday, but Amanda Wilson remembers her husband pausing to apply bug spray. Lifelong Mississippi residents and avid fishers, the Wilsons have heard all the horror stories about Vibrio vulnificus, a dangerous flesh-eating bacteria found in warm, brackish coastal waters and raw or undercooked seafood.