(CNN) -- A virulent strain of E. coli that has annihilated 18 people in Europe has not affected produce in the United States, along to food safety and health officials who conceded Friday there's much to learn about the organism.
Even as exertions persist to determine what caused the outbreak, cucumbers, tomatoes and lettuce imported from Germany and Spain will be tested and cleared before they are sold in the United States, according to David Elder of the Food and Drug Administration, and the results will be shared with the European Union.
"I want to accentuate that this outbreak has not affected the U.S.," Elder told journalists in a session cry. "Produce remains secure, and there is not cause for Americans to alter where they mart, where they purchase or what they eat."
Two adult women and an adult man who traveled final month to northern Germany remain hospitalized in the United States with hemolytic uremic syndrome -- a fashion of kidney failure -- said Chris Braden of the U.S. Centers for Disease Control and Prevention. Those 3 cases were reported in Massachusetts, Michigan and Wisconsin. A fourth human adult cruel diarrhea, yet was not hospitalized, he joined.
Two U.S. service members in Germany too amplified diarrhea, Braden said. "We have no expectation that this will spread in our nation."
The E. coli infection has spread to 12 countries and is blamed for by least 18 deaths -- know next to nothing of one reported in Germany. About 1,800 people have been sickened.
The European Food Safety Alert Network initially said enterohemorrhagic E. coli (EHEC), a strain of E. coli, was found in organic cucumbers originating from Spain, packed in Germany and distributed to assorted countries. But authorities have said that the source of the contamination has not been pinpointed.
The Robert Koch Institute, Germany's allied element responsible for ailment control and prevention, has exhorted German purchasers not to dine raw tomatoes, cucumbers and lettuce.
Germany and Spain list because a small fraction of produce that is sold in the United States in a given annual.
Officials said trailing the source of the illness could be laborious. If it, in truth, stems from the produce, the tomatoes, cucumbers and lettuce could have been eaten together in a salad.
"We don't understand but what is the occasion and each of these (vegetables), personally or maybe in some medley, seem as presumable offenders, so I don't meditation we understand enough to hypothesize at what point in the supply shackle contamination may have happened," said Don Kraemer of the U.S. Food and Drug Administration. "We don't understand which one that actually had the contamination in it."
The CDC is advising anybody U.S. citizens who have recently traveled to Germany to seek instant remedial attention if they begin to show symptoms of the bacterial infection.
Braden said officials were unable to identify the source for an outbreak of this E. coli strain in the republic of Georgia in 2009.
The tug namely extra general amid women and adults, he said, and officials are not decisive how it may be related with generate. "We have a lot to learn almost this particular creature," Braden said.
The officials told reporters the U.S. Food Safety Modernization Act signed at President Barack Obama this year provides steps that reduce the risk of E. coli at U.S. farms and product facilities.
"We believe prevention is superior to answering to one outbreak such for this one," Kraemer said.