Federal health officials have raised the death toll to 18 in an outbreak of listeria in cantaloupe.

The Centers for Disease Control and Prevention said Tuesday that they have confirmed 100 illnesses in 20 states, including Illinois. That figure includes the 18 deaths, none of which have occurred in Illinois thus far. The agency said it has confirmed two additional deaths in Colorado and one in Kansas since last week.

The death toll may continue to rise. Wyoming's state health department said it has confirmed another death in that state linked to the outbreak. CDC officials have said the symptoms of listeria can take up to two months to show up.

Jensen Farms in Holly, Colo. recalled its cantaloupes Sept. 14 after the farm's melons were traced to the listeria illnesses.