E. coli that has sickened thousands in Europe has become the deadliest outbreak of the bacteria on record as a rare strain is causing kidney failure in unprecedented numbers, U.S. health officials said.
At least 18 people have died and 1,823 cases have been reported, according to the World Health Organization in Geneva. The number of reported cases is based on hospital records, and the actual number of infections may be 10 or more times higher, said Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota.
The strain circulating in Germany and nine other European countries produces a toxin not usually seen in E. coli that can damage the kidneys and other organs. Germany alone has reported 520 cases of the kidney ailment and officials advised against eating raw tomatoes, cucumbers and leafy salads.
“We usually consider that a rare complication,” said Robert Tauxe, deputy director of food-borne illnesses at the U.S. Centers for Disease Control and Prevention in Atlanta, in a telephone interview. “This is a new public health problem.”
Germany’s Robert Koch Institute today confirmed 11 deaths related to the E. coli outbreak, as well as 520 cases of the potentially fatal complication, known as hemolytic uremic syndrome or HUS. Another 30 cases of HUS have been reported in Sweden, Spain, Denmark, the U.K. and the Netherlands, the European Centre for Disease Prevention and Control said today.
The biggest outbreak in the U.S. of a toxin-producing E. coli gave 41 people HUS. That event, caused by a different strain, occurred in tainted meat at the Jack in the Box fast-food chain in 1993, Tauxe said.
The E. coli found in Germany has killed more people and resulted in more cases of severe kidney damage than any outbreak on record, he said.
About 9,451 people were sickened and 12 killed in outbreaks in Japan from May 1996 to December 1996, according to a 1999 study in the American Journal of Epidemiology. The majority of those cases were acquired by tainted radish sprouts in school lunches. In Scotland, 17 deaths from E. coli were confirmed after an outbreak in November 1996, according to a government report.
The U.S. Food and Drug Administration is stepping up testing of imported foods, though vegetables in the U.S. should be safe to eat, Tauxe said.
The European fresh-produce market came to “an alarming standstill” after the outbreak, said Brussels-based Freshfel, which represents the fresh fruit and vegetable supply chain. European Union vegetable producers are losing “millions of euros a day” because of trade restrictions, according to Brussels-based farm group Copa-Cogeca.
Hamburg doctors are advising people to avoid eating raw vegetables to prevent infection.
“I tell people to wash their hands and wash the vegetables they eat,” Rolf Stahl, the director of the Department of Internal Medicine III and Clinics at the University Medical Center Hamburg-Eppendorf, Hamburg’s largest hospital, said at a press conference in Hamburg today. “Don’t eat fresh cucumbers, tomatoes or salad -- cook it and then you’ll be safe.”
While at least one shop in downtown Hamburg has removed cucumbers, tomatoes and lettuce from sandwiches, Jennifer Loose said she’s not afraid to eat raw vegetables.
“I’m eating vegetables, but I am buying them from a farmer nearby my home,” said Loose, a 24-year-old kindergarten teacher who lives in Hamburg. “That is better than the vegetables in the supermarket.”
Researchers and public health officials are at odds over whether the strain is one that has never been seen before. The variant, which produces a toxin related to the bacterium Shigella, is “highly unusual,” German and Swedish scientists said in a report in the weekly newsletter Eurosurveillance yesterday. The germ has caused food-borne outbreaks of diarrhea and HUS before, although outbreaks in Germany haven’t been reported previously, they said.
A Chinese laboratory working with German scientists said it sequenced the genes of the bacteria and found it to be a mutated strain that was unlike any previously identified.
The lab, Beijing Genomics Institutes in Shenzhen, said in a statement yesterday that it had conducted “a preliminary analysis that shows the current infection is caused by an entirely new super-toxic E. coli strain.”
The CDC’s Tauxe said in an interview yesterday that the report was “overstated.” Tauxe said the strain had previously caused an isolated case in Korea. Still, he said the European infections are the first known outbreak of the rare strain. The WHO agreed with Tauxe’s assessment in a posting to its website late yesterday.
“It depends on how you define ‘strain’” said Osterholm, of the University of Minnesota, explaining why researchers disagree over the germ’s novelty. The CDC, WHO and Osterholm agree the bacterium is a previously known variety called 0104:H4. The bug, however, has genetic traits that make it different from previous cases, Osterholm said. For example, it is highly resistant to antibiotics, and it lacks a gene previously thought to be key to causing kidney damage.
“This combination is absolutely new,” he said in a telephone interview. “Right now we need to trace down the source. That’s number one: to make sure this product is no longer in circulation.”
All humans and animals carry E. coli in their intestines, and those strains are usually harmless, according to the Stockholm-based ECDC. Some variants produce toxins and cause illnesses ranging from diarrhea and nausea to HUS, which typically occurs in about 5 percent of E. coli patients, according to the CDC.
“The strain is a new hybrid of two nasty E. coli strains that has gained a few tricks to cause more severe disease,” said Brendan W. Wren, head of the pathogen molecular biology department at London School of Hygiene & Tropical Medicine. “It is not uncommon for bacteria such as E. coli to mutate and evolve, because they multiply every 30 minutes and therefore have numerous chances to mutate.”
The resistance to antibiotics in laboratory testing suggests the strain may have originated in a geographic region with high levels of antibiotic use, possibly an area with domestic farm animals or in a developing country, Tauxe said.
The “epicenter” of the outbreak is the area surrounding the northern German city of Hamburg, said John Dalli, the European commissioner for health and consumer policy. Austria, Denmark, France, Netherlands, Norway, Spain, Sweden, Switzerland and the U.K. have reported cases, the WHO said. All infections found outside Germany, except for two, are in people who had recently visited northern Germany or had contact with a visitor from the area, according to the WHO.
Two E. coli cases were identified in the U.S. among travelers returning from Europe, according to the CDC.
There have been no shipments of tomatoes, cucumbers or lettuce from Germany to the U.S. since January, according to Dara Corrigan, the Food and Drug Administration’s associate commissioner for regulatory affairs. Three shipments of lettuce have come from Spain during that time period and one shipment of cucumbers arrived in May. No fresh tomatoes from Spain have been imported in the last 18 months.
“We’re going to keep an eye on what’s going on in Europe,” U.S. Agriculture Secretary Tom Vilsack said in a news briefing yesterday. “I have no reason to believe that specifically what happened in Europe is somehow going to come here.”
Infection with virulent strains of the bacteria can occur through contact with uncooked food or animals carrying the bacteria. The E. coli can live on leaves for as long as two weeks, said Paul Hunter, a professor of health protection at the University of East Anglia in England.
People who have symptoms, including stomach cramps and bloody diarrhea, should see their doctors, said Ian Jones, a professor of virology at the University of Reading in England.
“Once the damage is done, you may have kidney disorders for the rest of your life,” Jones said.