At least 13 people in eight U.S. states have died as a result of a listeria outbreak from contaminated cantaloupes, the Centers for Disease Control and Prevention said.

Besides the eight people confirmed dead as a result of the outbreak last week, state and local health departments in Kansas, Missouri, Nebraska and Texas have listed five more likely dead as a result of the tainted melons.

Of the 13 deaths, four were in New Mexico, two in Colorado, two in Texas and one each in Kansas, Maryland, Missouri, Nebraska and Oklahoma. 

The CDC reported Tuesday that 72 people in 18 states have fallen ill. The states that reported illnesses due to listeria-tainted cantaloupe are California, Colorado, Florida, Illinois, Indiana, Kansas, Maryland, Missouri, Montana, Nebraska, New Mexico, North Dakota, Oklahoma, Texas, Virginia, West Virginia, Wisconsin, and Wyoming.

Colorado, where the tainted cantaloupes came from, has the highest number of illnesses.

The number of deaths is only likely to grow since, as reported on USA Today, the incubation period for listeria is considerably long, and the fatality rate is high for groups like pregnant women, the elderly and those with compromised immune systems.

Investigators have traced the outbreak to cantaloupes grown at Jensen Farms in Granada, Colo., following the finding of listeria monocytogenes in a sample from there. The Food and Drug Administration has advised consumers to throw out the recalled melons.

Contaminated cantaloupes are believed to have been shipped to Arkansas, Arizona, California, Colorado, Idaho, Illinois, Kansas, Minnesota, Missouri, Montana, Nebraska, New Jersey, New Mexico, New York, North Carolina, North Dakota, Ohio, Oklahoma, Pennsylvania, South Dakota, Tennessee, Texas, Utah, Virginia and Wyoming.

Listeria is a dangerous bacteria that flourishes in cool temperatures and is particularly dangerous to the elderly or to people with weakened immune systems. There are about 800 reported cases a year in the United States, most of them linked to meat and soft cheese.

Listeria can grow in refrigerators or at room temperature, unlike other pathogens, and has an incubation period of about a month. The ease with which it can spread is leading officials to predict more canteloupe cases before the outbreak is over.