Center for Disease Control | MCT

Above: an election microscope image of an E. coli bacterium, a “quorum-sensing” microbe that can send and receive chemical signals from others like it, in effect conducting a head count of its neighbors. The little bugs are genetically programmed to wait until enough of them have assembled before they launch an infectious attack.

An outbreak of E. coli in St. Louis has, thus far, left Washington University students unscathed.

The St. Louis County Health Department has yet to find the cause of the breakout of over 30 cases in the area, which were originally rumored to be linked to salads at nearby Schnucks locations.

So far there have been no cases of E. coli on campus, according to Lisa Ross, Washington University’s director of clinical services. She said the University did not notify students of the outbreak because it did not pose a significant threat to the campus community.

“The dining services here are really careful, so I think eating campus food is safe,” Ross said. “If people [are] cooking their own food and take precautions, the likelihood [of contracting E. coli] should be fairly low.”

The St. Louis County Health Department came up with a list of suspect sources of the bacteria by interviewing the people who were infected by it.

Rodger Mallison | Fort Worth Star | MCT

A doctor works with a colony of laboratory-grade E. coli cells.

“Thus far, nothing explains more than about two-thirds of the cases, so we are still investigating because it is kind of a mystery at this point,” health department spokesman Craig LeFebvre said.

The county’s health department is not expecting any new cases tied to this outbreak.

“We haven’t had any new ones lately. All of them are clustered around a given incubation period time. If we don’t receive any new ones, then hopefully it’s the end of this particular outbreak,” LeFebvre said.

Ross said this strain was caused by the E. coli O157:H7 strain, commonly referred to as E. coli 157. The most common symptoms of E. coli 157 are abdominal cramping and bloody diarrhea. Severe cases can lead to such complications as kidney failure.

Ross urged anyone with symptoms of E. coli to go immediately to Student Health Services.

Most students noted that their eating habits have not changed significantly.

“This is where I have to eat, so I have to trust that the food here is good,” sophomore Cong Chang said. “It’s not like I can go off campus and eat or make my own food—[there’s] not enough time.”

Some agreed that they felt safe eating campus food.

“I trust Bear’s Den a lot, [but] I’ll probably be a little bit more weary of trying new places in St. Louis,” sophomore Amanda Packer said.

Others, however, did note concern with the possibility of E. coli despite the lack of documented cases on campus.

“I’ve stopped eating salads and stuff,” freshmen Beenish Qayum said. “[I’m] sticking to cooked things.”

The most common reservoir for E. coli bacteria is the intestine of cattle. Ross said that around 10 percent of healthy cattle in the United States carry E. coli and about 1 percent of retail ground beef has E. coli in it. If meat is fully cooked, however, the risk of contracting is E. coli is slim.

The most likely sources of E. coli are undercooked meat, unpasteurized milk products and produce that has been cross-contaminated with uncooked meat or cattle feces.