Kruse said it's not uncommon for (bacteria) to continually mutate, evolving and swapping genes. "There's a lot of (mobility) in the microbial world," she said. Kruse said it was difficult to explain where the new (strain) came from but said strains of bacteria from both humans and animals easily trade (genes), similar to how animal viruses like Ebola sometimes jump into humans.
"One should think of an animal source," Kruse said. "Many animals are hosts of various types of toxin-producing E. coli." Some scientists suspect the deadly E. coli might have originated in (contaminated) manure used to fertilize vegetables.
Previous E. coli outbreaks have mainly hit children and the elderly, but the European outbreak is disproportionately (affecting) adults, especially women. Kruse said there might be something particular about the bacteria strain that makes it more dangerous for adults.
But she cautioned that since people with (milder) cases probably aren't seeking medical help, officials don't know just how big the outbreak is. "It's hard to say how virulent (this new E. coli strain) is because we just don't know the real number of people affected."
Nearly all the (sick) people either live in Germany or recently traveled there. Two people who were (sickened) are now in the United States, and both had recently traveled to Hamburg, Germany, where many of the (infections) occurred.
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