As Labs Test For E. Coli, Cases Mount Missed Bacterium Incidents ‘Shock’ Federal Epidemiologist

The deadly E. coli bug strikes more frequently than health officials had suspected, often causing symptoms that go unrecognized or unreported.

As more laboratories test for the bacterium - known as Escherichia coli O157:H7 - they’re discovering more and more isolated victims who aren’t part of an outbreak, the Centers for Disease Control and Prevention reported Thursday.

The CDC estimates that as many as 20,000 people fall sick each year with E. coli diarrhea and stomach cramps. About one-third of the victims are hospitalized, and a few hundred die, mostly children and the elderly, according to the CDC.

Most people catch the bacterium from undercooked hamburger and other contaminated food. There is no treatment.

In a report on a suspected outbreak in New Jersey, the CDC said just five cases were reported from June 1 to July 27, 1993, but there were 46 cases in the same period a year later in the same state. The CDC found that the increase resulted from a jump in the number of labs looking for E. coli - from two to 18.

“It was a shock,” said Dr. Paul Mead, a CDC epidemiologist. “These are the cases we’ve been missing all along. This is a very big problem.”

Doctors usually don’t think about E. coli and often confuse its symptoms with those of appendicitis, colitis and other diseases, according to the CDC. And the agency estimated that only 29 percent of the nation’s clinical laboratories test all diarrhea samples for E. coli.

E. coli O157 gained wide attention in 1993 when it sickened at least 500 people who had eaten undercooked Jack in the Box hamburgers in Washington state. Three children died.