Sep 19, 2006 (CIDRAP News) – The tally of people involved in a nationwide Escherichia coli O157:H7 outbreak associated with fresh spinach jumped by 17 today to reach 131, about half of whom were hospitalized, the US Food and Drug Administration (FDA) reported.
At a press conference this afternoon, David Acheson, MD, chief medical officer for the FDA’s Center for Food Safety and Applied Nutrition, said two more patients developed hemolytic uremic syndrome (HUS), which can cause kidney failure and death, bringing HUS cases to 20. Nationwide, he said, 66 patients have been hospitalized with the illness. The death toll remained at one today, and the number of affected states stayed the same at 21.
Six people in the outbreak (5%) were younger than 5 years, and 96 (73%) were women, the Centers for Disease Control and Prevention (CDC) said in an update today. Of patients who gave the date when their symptoms began, 93% fell ill between Aug 19 and Sep 5.
The FDA first announced the outbreak on Sep 14 when it advised consumers to avoid eating fresh spinach or any products containing it, because most patients said they had consumed fresh spinach. Two producers—Natural Selection Foods and River Ranch—have voluntarily recalled their products that contain fresh spinach.
Acheson said it's too early to make a definitive statement on the virulence of the involved E coli strain, but he said the number of people who have been hospitalized seems high. In a typical E coli outbreak, he said, 25% to 30% of patients require hospital treatment.
Acheson said the number of patients who have had HUS is also high; normally, HUS only afflicts 5% to 10% of patients.
Investigators have taken spinach samples at production facilities and from bags sent in by consumers, Acheson said. Test results are expected in the next 3 or 4 days.
Teams of investigators are currently taking samples at nine farms that were growing spinach for Natural Selection Foods at the time of the outbreak. All the farms were linked to product codes on fresh spinach bags submitted by patients, he said. Monterey County, Calif., which includes the part of the Salinas Valley where much of the spinach is grown, has 10,480 acres devoted to spinach farming.
"Probably, we have a single location that further contaminated large volumes of spinach," Acheson said.
Wisconsin has the highest number of cases with 32, including the one death. Most states have from 1 to 9 cases. Acheson speculated that Wisconsin might have received a disproportionate share of the tainted spinach.
Yesterday, Natural Selection Foods said that none of the bags submitted by patients were from its organic brands. However, Acheson said the FDA has not ruled out the organic products as a culprit.
The FDA continues to receive reports of new cases and new information on brands, he said. "We have not ruled out other recalls as our active investigation expands," Acheson said.
The CDC said this week that people who experience diarrhea after eating fresh spinach or salad blends containing fresh spinach should contact their healthcare provider and ask that their stool sample be tested for E coli O157:H7.
Sep 19 FDA press release
CIDRAP overview of pathogenic E coli