They said they're now investigating 27 cases: nine confirmed and 18 suspected. The common denominator is all attended the North Carolina State Fair.
That's frustrating for Agriculture Commissioner Steve Troxler. There was another outbreak linked to the fair in 2004, and since then, officials have gone to great lengths to prevent any new ones.
"Today we're sitting here, we don't have a clue and neither does public health, as far as I know, about what could have happened," said Troxler. "We had put a ton of measures in place to try to prevent another outbreak."
The plan now is to follow a similar playbook to 2004: talking to victims and their families and making changes based on what they find.
"We're involved in this, I can guarantee you, every day at some level - doing things internally to look at what went on, how did it go on, and we're still puzzled as to how in the world this could have happened," said Troxler.
Troxler's concern is how to prevent future outbreaks and convincing visitors the fair is safe without killing its appeal.
"We can eliminate the people, the food, the rides, the animals and the exhibits, and it'll be safe, but that's not a state fair," said Troxler.
So the mission is to pinpoint the cause if at all possible, and for Troxler, it's personal.
"My grandkids - three of them there multiple times - my 84-year-old mother, my wife, a daughter-in-law that was pregnant, she was there - everybody's got skin in this game," he explained.