FORT WAYNE, Ind. (WOWO) — Northeast Indiana is accounting for roughly half of Indiana’s nearly 1,900 reported cyclosporiasis cases, raising questions about why the region has seen such a high number of infections.

Data from the Indiana Department of Health and the Centers for Disease Control and Prevention shows Indiana has one of the highest numbers of reported cyclosporiasis cases in the country, behind only Michigan, Ohio and Missouri, according to 21Alive.

The latest numbers show a significant difference between northeast Indiana and other parts of the state.

Marion County, which has a larger population than all of northeast Indiana combined, has reported 132 cases. Lake County has reported 19 cases, despite having about 100,000 more residents than Allen County.

DeKalb County Health Officer Dr. Mark Souder says interviews with residents who tested positive repeatedly pointed to Taco Bell as a possible common exposure.

Souder said he believes lettuce supplied by Taylor Farms out of Mexico and distributed through Taco Bell locations in the region may be responsible for the high number of cases in northeast Indiana.

The CDC has linked iceberg lettuce from Taylor Farms to the broader cyclosporiasis outbreak, but says other potential sources are also being investigated.

Souder also believes the actual number of cases in northeast Indiana could be eight to 10 times higher than reported because many people recover without seeking treatment or getting tested.

Cyclosporiasis is an intestinal illness caused by the Cyclospora parasite. Symptoms can include frequent, watery diarrhea, along with other gastrointestinal symptoms.

Anyone who believes they may have cyclosporiasis is encouraged to contact a health care provider and get tested.