The number of people who have fallen ill from E. coli-tainted romaine lettuce grown in the Yuma, Arizona, region has risen to 98, the CDC announced on April 27.
More than half the victims became ill enough to be hospitalized and the CDC said consumers should not eat any romaine or romaine-containing products unless they know that the lettuce did not originate from the Yuma region.
The strain of Escherichia coli seen in the outbreak is known to be particularly severe.
Ten of the 46 people hospitalized have hemolytic uremic syndrome. There have been no deaths in the outbreak, which began on April 20th and has now spread to 22 states, most recently Mississippi, Tennessee, and Wisconsin.
The hospitalization rate of 53 percent is significantly higher than the typical rate for an E. coli outbreak, which is about 30 percen, Matthew Wise, the CDC’s deputy branch chief for outbreak response told reporters during a conference call.
The E. coli involved produces the Shiga toxin, which typically generates symptoms within three to four days. Those symptoms include severe stomach cramps, vomiting, and diarrhea that is often bloody. Recovery typically takes a week but the illness can be persistent.
Wise predicted that the number of cases will rise in the coming days because it can take two to three weeks to confirm each new case as part of an outbreak.
In the meantime, when it comes to romaine, “If in doubt, don’t buy it or don’t eat it,” he said.
One Yuma farm has been identified as the source of cases in an Alaskan correctional facility but lettuce originating from more than two dozen other area farms may also be tainted, Wise said.
Although the farm that grew whole heads of romaine that made people sick in Alaska has completed its harvest, “We haven’t been able to guarantee that no (additional) product is coming out of Yuma,” said Stic Harris, director of the Coordinated Outbreak Response and Evaluation Network at the U.S. FDA.
Harris said other people who have fallen ill ate romaine coming from other Yuma farms, and the farms themselves may not be the source.
“We have not determined where in the supply chain the contamination occurred. We are continuing to examine all possibilities, including that contamination may have occurred at any point in the growing, harvesting, packaging, and distribution chain before reaching the Alaskan correctional facility,” he said.
Wise said this is now the largest Shiga toxin outbreak in the U.S. since a 2006 outbreak linked to tainted spinach felled more than 200 consumers.