JEFFREY BROWN: Next tonight, a new food scare in Europe, in an age when the fruit and vegetables on your table can come from just about anywhere.
Ray Suarez has the story.
RAY SUAREZ: Scientists in this German laboratory worked today to find out more about the deadly form of E. coli that's afflicting Europe.
HOLGER ROHDE, University Medical Center Hamburg-Eppendorf (through translator): We were able to determine that this is a new strain, a version of the pathogen not seen before.
RAY SUAREZ: Preliminary testing indicates it may be a mutated form of two E. coli bacteria, which may explain why this outbreak is so widespread and dangerous. At least 18 people are dead so far, 1,600 people are sick.
Cucumbers, raw lettuce and tomatoes are the prime suspects, but the source of the outbreak has yet to be identified. The illness has spread to at least 10 European countries, and Russia today banned the importation of all vegetables from the European Union.
The move was praised by Russians.
MAN (through translator): About the ban on importing vegetables from Europe, it's absolutely the right decision, as if we didn't have our own. We need to support our own producers.
RAY SUAREZ: But E.U. leaders said the Russian action was disproportionate.
Overall, Germany has been hardest-hit, with nearly all the victims either living there or having recently traveled to the country. Initially, the Germans said the E. coli came from Spanish cucumbers, but that turned out not to be true.
ILSE AIGNER, German agriculture minister (through translator): The source simply cannot be clarified yet. It is clear that these bacteria have appeared in humans and we are working nonstop to find out where they have come from.
RAY SUAREZ: Spain says lost sales are costing its farmers $287 million a week. And despite an agriculture minister enjoying one on television, many are still afraid to buy Spanish cucumbers.
ALVARO TORRES, food seller (through translator): Shoppers don't say anything, but they are not buying cucumbers. Now, we are in season for high sales of cucumbers. When it gets hot, it is used in gazpacho and salads, but we are hardly selling any at all.
AMELIA MONTERO, shopper (through translator): My husband likes them a lot, and so do I. But, at the moment, I am going to wait.
ANTONIO ARAUJO, shopper (through translator): I am not frightened. I eat cucumbers every day. This thing about the cucumbers is a piece of nonsense invented by the Germans.
RAY SUAREZ: Previous E. coli outbreaks have mainly hit children and the elderly, but this one is disproportionately hitting adults in a way that hasn't before been seen.
ERIK OLSON, Pew Charitable Trusts: This form of E. coli seems to be attacking people's kidneys and making people sick in a way that seems to be unusual, and is much more dangerous than some of the other strains that we have seen before.
RAY SUAREZ: More than 450 victims have developed a rare complication, kidney failure. For now, officials are struggling to halt the outbreak and pinpoint the cause. And some scientists think the answer is in sight.
HUGH PENNINGTON, University of Aberdeen: Clearly, this is a German problem. It is German food that has caused the outbreak. It may be entirely a German problem, not food produced anywhere else and imported into Germany. And there's no evidence that food anywhere else, eaten anywhere else has caused any cases at all.
RAY SUAREZ: But nailing down the final answers won't be easy, in an age when countries no longer rely exclusively on their own farmers and import much of what they eat.