Washington, April 12 - E. coli and Salmonella infections are on the rise in the United States, but other foodborne illnesses appear to have leveled off, the Centers for Disease Control and Prevention said on Thursday.
Data from 10 states show that infections caused by Campylobacter, Listeria, Shigella, and Yersinia have all fallen since the 1990s -- a success story.
But after falling sharply in 2003 and 2004 when the meat industry pulled together to make ground beef safer, rates of E. coli 0157:H7 infections have rebounded, and many appear to be related to outbreaks in fresh produce, the CDC said.
"As recent outbreaks have shown, too many people in the United States are getting sick each year from foodborne illnesses," CDC Director Dr. Julie Gerberding told reporters in a telephone briefing.
"For instance, the outbreaks involving tomatoes, lettuce and spinach underscore the need to more effectively prevent contamination of produce," Gerberding added.
"We're also working to strengthen our ability to quickly detect and identify foodborne illnesses. We know the faster we can detect an outbreak, the faster we can take actions that will help protect people."
The CDC identified 17,252 laboratory-confirmed cases of food poisoning in 2006 using its FoodNet surveillance tool, which looks in detail at foodborne illness in 10 states, covering 45 million people or 15 percent of the total U.S. population.
These included 6,655 cases of Salmonella, 590 cases of E. coli O157, an additional 290 cases of other disease-causing strains of E. coli, 138 cases of Listeria and 41 cases of Cyclospora.
All these microbes cause a range of illnesses but are mostly marked by diarrhea and often nausea. In extreme cases, some can cause hemolytic uremic syndrome, which can destroy kidney function, and infection can attack other organs.
The CDC figures do not include details on deaths.
Last September, E. coli bacteria in uncooked spinach from one California farm and made 300 people sick in 26 states and killed three.
The survey also found that cases of Vibrio infection, usually linked to shellfish, increased by 78 percent, to 154 cases in 2006.
"People are simply eating more ... shellfish and this creates the opportunity for more exposures and more infections," Gerberding said.
The CDC estimates that 76 million people in the United States get sick every year with some sort of foodborne illness and that 5,000 die, but Gerberding said this is a rough estimate because it is so hard to track.
"Our medical system often doesn't encourage clinicians to order a stool culture when a patient comes in with a diarrheal illness that may be food-related," Gerberding said.
Thus doctors and patients may never discover whether a person was infected by food or something else.