BEAVER COUNTY, PA. Source of hepatitis A still eludes investigators

The source of about half of all hepatitis A cases is never determined.
PITTSBURGH (AP) -- Investigators have interviewed and re-interviewed hundreds of people in attempts to trace the source of a recent hepatitis A outbreak in Pennsylvania, a task that has perplexed health officials in other states after previous infections.
The Pennsylvania Department of Health, which is leading the investigation into an outbreak that sickened more than 500 people and led to three deaths, has yet to pin down how the virus found its way into a Mexican restaurant at a Beaver County mall.
The official number of people sickened in the Pennsylvania outbreak remained at 510 on Sunday, though the number of people who had received antibody inoculations was closing in on 9,000.
The investigation has shifted to the possibility that produce brought to the restaurant might be the culprit. If or when investigators do find the vehicle of infection, determining how it became infected with the liver-attacking virus can be a formidable endeavor.
Outbreak in South
During an outbreak earlier this fall, investigators in Tennessee and Georgia excluded dozens of possible sources of an outbreak in at least 12 restaurants before finding the source.
It took 18 days before investigators in Georgia determined the likely carrier was green onions, the same food that carried the virus at a restaurant in Knoxville, Tenn. But the investigation goes on, officials in Georgia told the Pittsburgh Post-Gazette.
"The contamination of the onions could occur anywhere between the fields and putting them on the table," said Dr. Paul Blake, Georgia's state epidemiologist. "Where did it occur? I don't think anybody knows."
Health officials in Pennsylvania have yet to exclude a human carrier, though the pattern of the virus' spread and information gleaned from interviews has led them to believe the source was some sort of food.
Between 125,000 to 200,000 people each year contract hepatitis A. It can be spread by an infected person who does not wash his hands before handling food or utensils. It can also be spread on uncooked foods, such as salads.
Green onions pulled
Chi-Chi's, where investigators have linked the most recent outbreak, has pulled green onions from the shelves of all 100 of its restaurants as a precaution.
The state Department of Agriculture has provided information as to the possible route produce shipped to Chi-Chi's may have taken.
Growers, distributors and transportation companies that have some role in food used in Beaver County restaurants, including Chi-Chi's, are based in Kentucky, Texas and California, according to the Pennsylvania Department of Agriculture, which regulates the shipments.
The source of about half of all hepatitis A cases is never found, health officials said. That job becomes more difficult with each passing day.
Health officials in Georgia had hoped the same strain that sickened 210 people in the Atlanta area was the same that sickened 80 people around the same time in Knoxville, Tenn., this fall.
Scientists now believe that the strains are not related, a development that Blake, Georgia's epidemiologist, calls a tough break.
"Why they would occur at the same time?" he asked. "I just don't know."