Wednesday, Captain Adam Myrick said 120 inmates have been treated for the illness in the past two days.
Myrick said that number Thursday is now at 131 inmates.
Myrick noted that epidemiologists with DHEC are investing the illness to determine what it is and how it is spreading.
Jim Beasley with DHEC said initial tests conducted by DHEC have found salmonella.
The inmate population at the detention center was 762 as of Wednesday.