CHARLESTON - Local health department officials are still trying to track down the source of E. coli bacteria that infected three area residents earlier this month, although at least one of the incidents has been traced to an Effingham restaurant.

The local cases - two in Coles County and one in Cumberland County - were reported at least a week ago, officials said. Officials at the Coles County Health Department haven't found what led to the infections in this county, according to Cathie Reynolds, the department's nursing director.

"There doesn't appear to be anything in common between the two cases," she said.

But the Cumberland County victim has been linked to a reported E. coli outbreak at the El Rancherito restaurant in Effingham, according to Janet Stierwalt, administrator.

Meanwhile, the Effingham County Health Department is asking that everyone who ate at the Effingham El Rancherito this month contact the department, regardless of whether they have become infected. The department's phone number is 342-9237.

Crystal Schutzbach, the Effingham County Health Department's communicable diseases coordinator, said the department has six confirmed cases of people being infected with E. coli. All of them ate at the El Rancherito in Effingham between Sept. 11 and 13, she said.

The restaurant closed voluntarily Thursday and is being "very cooperative," Schutzbach said. The department hasn't determined what the problem was at the restaurant that led to the infections, she added.

All the confirmed cases in Effingham County are residents of that county, according to Schutzbach, and one of the people infected is still hospitalized.

Reynolds said the most common way people become infected by the bacteria is by eating rare or under-cooked meat, but it can also be present on unwashed lettuce or unpasteurized milk or juice. People can pass the bacteria to one another if they don't wash well enough after using the restroom, she added.

Another food item with which to be careful this time of year is apple cider, as some cider isn't pasteurized, she noted.

"People should just be careful about what they're eating and make sure they're washing well," Reynolds said.

Symptoms of E. coli infection are cramping and severe diarrhea and bloody stools, but no fever, she said. Schutzbach said people who think they might be infected by E. coli should not take medicine for diarrhea before they see a doctor.