The number of patients reported in the ongoing Escherichia coli outbreak linked to onions served at McDonald’s restaurants has grown to 104 people across 14 states. Of 98 people with information available, 34 have been hospitalized, four people developed hemolytic uremic syndrome (HUS), and one person has died.

Previously, patients sickened in this outbreak had only been identified in 13 U.S. West and Midwest states, however, a patient has recently been reported in North Carolina.

All but one of the 81 case patients interviewed reported eating at McDonalds, and 63 of the 75 people who can remember the specific items they ate reported an item containing fresh slivered onions.

The U.S. Food and Drug Administration (FDA), the Colorado Department of Agriculture, and the Colorado Department of Public Health and Environment have collected onion and environmental samples from McDonald’s restaurants, distribution centers, and companies of interest for laboratory analysis. At present, only one FDA sample of recalled onions has tested positive for E. coli, but it is non-O157:H7 Shiga toxin-producing E. coli (STEC) and does not match the outbreak strain or any other clinical illnesses. Whole genome sequencing (WGS) analysis determined that the sample is positive for E. coli O168:H8 and contains the Shiga toxin gene stx2a. Additional sample results are pending.

Previously, the U.S. Centers for Disease Control and Prevention (CDC) named a Taylor Farms facility in Colorado Springs, Colorado as the source of the onions served at McDonald’s and implicated in the outbreak. Taylor Farms initiated a recall of the onions, and McDonald’s—as well as other restaurant chains supplied by Taylor Farms—removed fresh onions from their menus at affected locations.

FDA completed onsite inspections at the Taylor Farms Colorado Springs facility and an onion grower of interest in Washington state, although FDA has been unable to definitively implicate the grower.

Beef patties used at McDonald’s have been ruled out as the cause of sickness.