Most of the Listeria illnesses in Colorado, including one that resulted in death, have now been tied to a multistate outbreak that includes Nebraska and Texas and may have been caused by contaminated cantaloupe.

The Colorado Department of Public Health and Environment on Friday said nine of its 13 confirmed listeriosis cases since August 1 are now linked to two cases in Texas and one in Nebraska that are believed to have stemmed from the consumption of contaminated cantaloupe.

Colorado public health officials said the four other Listeria cases reported since August 1, a cluster that also includes one death, either have laboratory results pending or have already been excluded from the group that includes Texas and Nebraska.

They said cantaloupe is the “likely source” of the Listeria for the dozen case patients in the Colorado-Texas-Nebraska group.  

The Centers for Disease Control and Prevention (CDC) is coordinating the multistate investigation with affected states, the Food and Drug Administration (FDA)  and the U.S. Department of Agriculture’s Food Safety Inspection Service (FSIS). 

Colorado officials no specific source, foreign or domestic, for the cantaloupe has been identified. They said all of the ill Colorado residents in the multistate group reported eating cantaloupe prior to becoming sick.

Victims of Listeria in Colorado since August 1 have all required hospitalization and two have died.

Confirmed Listeria cases in Colorado have been reported from Adams, Arapahoe, Boulder, Denver, Douglas, El Paso, Jefferson, Larimer and Weld counties located up and down the Front Range of the Rocky Mountains.  The patients range in age from 30 to 90. Their average age is 84. The majority are women. 

Dr. Chris Urbina, chief medical officer and executive director of the Colorado Department of Public Health and Environment, said, “While the investigation into the source of the Listeri

outbreak is continuing, it is prudent for people who are at high risk for Listeria infection to avoid consumption of cantaloupe.” 

People who are at high risk for listeriosis include people age 60 and older; people with weakened immune systems from transplants or certain chronic diseases, immunosuppressive therapies or medications; and pregnant women. Healthy adults rarely develop this illness. 

Dr. Urbina said, “While the initial investigation has identified cantaloupe as a common food item the ill people reported eating, it also is important for people at high risk to follow the standard CDC guidance about Listeria. People can decrease their risk of Listeria infection by avoiding deli meats unless reheated to an internal temperature of 165 F, refrigerated pâté or meat spreads, refrigerated smoked seafood, and soft cheeses such as queso fresco and brie unless they are made with pasteurized milk.” 

Eating food contaminated with Listeria monocytogenes can cause listeriosis, an uncommon but potentially fatal infection. Symptoms of listeriosis can include fever and muscle aches, and also can include diarrhea, headache, stiff neck, confusion and convulsions. Listeriosis also can cause miscarriages and stillbirths. 

Antibiotics given promptly can cure the illness and prevent infection of a fetus. Even with prompt treatment, some Listeria infections result in death. This is particularly likely in older adults and in people with other serious medical problems. 

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