An additional six cases of E. coli have been linked to burgers eaten at the Glasgow Hydro arena, bringing the total number ill to 21. The cases first began appearing several weeks ago. Some attendees who ate burgers at the arena between Jan. 17 and Jan. 19 have fallen ill with symptoms of E. coli O157:H7 infection, which includes diarrhea, stomach cramps and nausea. Health officials are asking anyone who attended events at the arena within those three days and then fell ill with similar symptoms to contact a healthcare provider to record their case. All of those who fell ill are recovering at home by this point. Investigators have not conclusively linked the illnesses to the burgers, but they said that burgers appear to be the most likely source of infection.