OMAHA, Neb. (AP) — The public campground at Lake Cunningham near Omaha’s airport has been closed after testing showed traces of E. coli in the well water.

The campground was closed Thursday after a water sample tested Wednesday showed the presence of E. coli.

E. coli is a bacterium that can cause bloody diarrhea, dehydration and, in the most severe cases, kidney failure. The very young, the elderly and those with weak immune systems are the most susceptible.

Water samples are taken weekly and tested by the Nebraska Health Department.

Officials say the state will treat the water before the campground can reopen.

Campers using the Lake Cunningham campground will get a refund and have the option to move to the nearby NP Dodge campground.