FOND DU LAC COUNTY -- 18 people are dead after testing positive for the Elizabeth Kingia bacteria.
But experts say it's not something healthy people should fear
"It may be that otherwise healthy individuals have been able to fight of this bacteria" says Stephanie Smiley with the Wisconsin Department of Public Health.
All of the 44 people infected in Wisconsin since November had pre-existing health conditions, and many were over 65 years old.
But it's not clear if those who passed away with the bacteria in their bodies died because of it or other serious health problems they had.
The Centers for Disease Control is working with the State Department of Health to figure it out
"They're looking for information about where patients have been, its a broad investigation at this point." says Smiley.
But there has been one good answer in that investigation
"It is not spreading person to person we know that it is not in the air like a cold or flu."