Federal investigators said salmonella samples found in chicken feed and manure found at Wright County Egg in Iowa matches the strain of salmonella that has sickened people across the country.
As investigators turn up more clues, the number of people thought to have been made ill by bad eggs is expected to grow.
Centers for Disease Control and Prevention officials say they normally see around 900 cases of salmonella from May through August each year. But since May, the number of cases has soared to more than 2,400.
The upshot: nearly 1,500 people so far have likely been infected with salmonella from contaminated eggs. No deaths have been reported.
The two companies' recalls have affected more than half a billion eggs.
Hillandale gets feed and young chickens from Wright County, which is at the center of the government's investigation. "We consider the current identified sources as responsible for the cases we're seeing," said the CDC's Dr. Christopher Braden said in a media briefing today.
But in the same call, FDA Associate Commissioner Joshua Scharfstein cautioned, "The feed facility could actually just be part of the general contamination through the farms," noting it could come into facilities through rodents or other birds.
Meanwhile, Democratic Rep. Henry Waxman of California has asked top officials at both egg facilities to testify before his committee next month.
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