Friday, July 15, 2005
By Tim Knauss
Staff writer
An unidentified elderly person Thursday became the fourth patient found to have listeriosis in Onondaga County, where health officials are still trying to pinpoint the source of the food-borne bacterial illness.
Lab tests have established that three previous cases, which surfaced last week, were caused by the same strain of listeria, indicating they probably came from a single source of contaminated food, said Dr. Cynthia Morrow, health commissioner.
It will take about a week to determine whether the fourth case was caused by the same strain, but for now investigators are looking for a common source, Morrow said.

Unfortunately, tracking the source is difficult because the disease incubates for up to 70 days before the person gets sick, Morrow said.
Listeriosis can be fatal, but severe symptoms are unusual in healthy adults and children; the disease most often affects pregnant women, newborns or people with weakened immune systems.
Morrow said she would not be surprised to see another local case of the rare disease.
“There’s a good probability that, whatever that source is, it’s no longer out there,” she said. “But because the incubation period is so long, we may see people who get sick even a month from now.”
The listeriosis patient identified Thursday is being treated at a local hospital and appears to be improving, Morrow said. The three patients who came down with symptoms last week also are improving, she said. Two are still in the hospital; the third has been discharged.
For more information about listeria, visit www. or call the county health department at 435-3236.
Contact reporter Tim Knauss at or 470-3023.