The Robert Koch Institute said 470 people in Germany were suffering from hemolytic uremic syndrome, or HUS, a number that independent experts called unprecedented in modern medical history. HUS normally occurs in 10 percent of EHEC infections, meaning the number seen in Germany could be expected in an outbreak three times the size being currently reported.
That discrepancy could indicate that a vast number of cases havenâ€™t been reported because their symptoms are relatively mild, medical experts said.
But they also offered another, more disturbing theory â€” the strain of EHEC causing the outbreak in Europe could be more dangerous than any previously seen.
â€œThere may well be a great number of asymptomatic cases out there that weâ€™re missing. This could be a much bigger outbreak than we realize right now,â€ said Paul Hunter, a professor of health protection at the University of East Anglia in England. â€œThere might also be something genetically different about this particular strain of E. coli that makes it more virulent.â€