The findings have led investigators to believe that the patients all got ill from ingesting the same contaminated food source.
"The problem is that we still don't know what the source is," said James McCurtis, spokesman for the Michigan Department of Community Health.
Within the last two weeks, 27 students at MSU fell ill with bloody diarrhea, including seven who needed to be hospitalized. Stool samples in eight of the patients showed that E. coli 0157:H7 was the culprit. It's a common, yet dangerous strain that killed several children in 1993 after they ate undercooked hamburgers at Jack in the Box restaurants.
Health investigators centered their food-history investigation at MSU's east complex dorms -- Akers, Holmes, Hubbard and McDonel halls -- where the majority of the students with confirmed E. coli sickness live, said Dr. Dean G. Sienko, director of the Ingham County Health Department.
However, knowing that the cases are linked to others statewide may mean the contaminated food was distributedly widely.
Lab test results, called DNA fingerprinting, for three MSU students matched those of patients who became sick from E. coli in Washtenaw, St. Clair, Wayne and Lenawee counties since Sept. 8, McCurtis said. The Washtenaw County case was a U-M student and the five in Lenawee County were inmates in the jail, McCurtis said. Details were unavailable on the cases in St. Clair and Wayne counties.
Investigators are continuing with detailed interviews to figure out what the MSU students ate. It's a complex process, Sienko said, that involves comparing their food histories to those of a sample population of well students.
All the MSU students have since been released from the hospital. The university has remained in close contact with its food vendors to assure safety of the food supply, MSU leaders say. No university dining halls have needed to close.