It looks like the flu.
"It causes an intestinal illness. Usually fever, abdominal pain and significant diarrhea," says Dr. Thomas Felger, St. Joseph County Health Officer.
But it spreads fast. Right now, it's spread to at least six South Bend schools. It's called shigellosis.
"It's not unusual to have one a month, maybe two. What's unusual is that in the daycare setting, it spread very quickly."
It was first found in daycares in August. Four new cases were reported just yesterday. Making 25 total.
"You can be exposed to the bacteria, have it pass through you and not really get sick with it, but you're still going to be contagious."
Which is why the Department of Health and South Bend schools are taking action to stop it.
In daycares, "They've been very cooperative and I don't know how many thousands of times they've disinfected their areas," says Felger.
And in schools.
"Parents were notified that the best way to prevent the spread of disease is to do proper hand washing," says School Nurse Manager, Sue Cullen.
They sent a letter with elementary and middle school students and, "We are educating custodians who clean our buildings to make sure bathrooms are cleaned appropriately with proper disinfectants, as well as door knobs, desks, anything kids come in contact with," says Cullen.
They aren't stopping there.
"School bus drivers were also notified so they can clean the buses properly, as well."
All the precautions may be slowing down the spread.
"Right now it's being well controlled. We don't really have many cases at this point," says Cullen.
And many are hoping it clears up fast.