E. Coli Outbreak From Sprouts, German Investigators Say

German investigators followed twisted trail to source of outbreak.

June 10, 2011— -- Investigators have identified German vegetable sprouts as the source of the deadly European E. coli outbreak that has killed 31 people and sickened nearly 3,100, according to an announcement today.

The outbreak might be one of the deadliest in modern history involving the foodborne pathogen. Reinhard Burger, president of the Robert Koch Institute, Germany's national disease control center, told reporters today that the pattern of the outbreak had produced enough evidence to implicate the sprouts even though no tests on sprouts from an organic farm in Lower Saxony had come back positive for the E. coli strain behind the outbreak.

"In this way, it was possible to narrow down epidemiologically the cause of the outbreak of the illness to the consumption of sprouts," Burger said at a news conference with the heads of Germany's Federal Institute for Risk Assessment and its Federal Office for Consumer Protection. "It is the sprouts."

Burger said all the tainted sprouts might have been consumed or thrown away by now but, he warned, the crisis is not yet over and people should still avoid eating sprouts.

From the beginning, the outbreak has led disease investigators through a twisted maze of clues with many dead ends. Dr. Gerard Krause, an outbreak investigator with the Robert Koch Institute, told ABC News this week that findings had implicated lettuce, tomatoes and cucumbers. Authorities have since lifted warnings against eating these vegetables, but not before E. coli fears led to the disposal of many of these vegetables in recent days.

Additional findings, including the detection of non-lethal E.coli on beet sprouts from the Netherlands, led to general fears about produce from the European Union. Russia and Saudi Arabia issued blanket bans on vegetable imports from the EU, and EU farmers claimed to be losing up to about $611 million a week as demand plummeted and ripe produce was left to rot. The EU pledged Wednesday it would offer farmers compensation of up to $306 million for the E. coli losses, according to the Associated Press.

The breakthrough that sprouts were to blame came after an expert team from the three institutes linked separate clusters of patients who had fallen sick to 26 restaurants and cafeterias that had received produce from the organic farm.

"It was like a crime thriller where you have to find the bad guy," Helmut Tschiersky-Schoeneburg of the consumer protection agency told the AP.

"They even studied the menus, the ingredients, looked at bills and took pictures of the different meals, which they then showed to those who had fallen ill," said Andreas Hensel, head of the risk assessment agency.

Oddly, the infections disproportionately affected adult women; normally, high-risk groups include young children and the elderly, Aphaluck Bhatiasevi, a communications officer with the World Health Organization (WHO), told ABC News.

As of last week, the U.S. Centers for Disease Control and Prevention said there were four suspected cases in the United States, individuals who likely contracted the infection while in northern Germany and brought it back to the country. Three of the victims are hospitalized with a serious E. coli-linked kidney condition known as hemolytic-uremic syndrome, and the fourth reported bloody diarrhea consistent with the outbreak strain of E. coli.

Hygiene Key to Avoiding Spread

Two U.S. military service members stationed in Germany were also suspected cases. The CDC said both of them had a similar diarrheal illness.

While the outbreak has thus far had a relatively small impact in the United States, disease control experts say there are ways to be sure that any illness that might be caused by the outbreak isn't spread.

In addition to avoiding contaminated food, good hygiene is the most important way to minimize transmission.

"It's also spread through contaminated feces," said Dr. Maria Alcaide, an assistant professor of infectious diseases at the University of Miami's Miller School of Medicine. "Anyone who is sick should wash their hands, and their caregivers should as well."

Anyone who starts noticing any symptoms should get to a doctor.

"If anybody gets very bad, bloody diarrhea, they should get medical care immediately," Alcaide said, "and providers should also be aware of what's going on with the situation."

The Associated Press contributed to this report.