Listeriosis Associated with Cantaloupe

Listeriosis is caused by Listeria monocytogenes, a gram-positive bacillus common in the environment and acquired by humans primarily through consumption of contaminated food. Infection causes a spectrum of illness, ranging from febrile gastroenteritis to invasive disease, including sepsis and meningoencephalitis. Invasive listeriosis occurs predominantly in older adults and persons with impaired immune systems. Listeriosis in pregnant women is typically a mild flu-like illness, but can result in fetal loss, premature labor, or neonatal infection. The incubation period ranges from 3 to 70 days.

On September 2, 2011, the Colorado Department of Public Health and Environment notified CDC of seven cases of listeriosis. By September 29, 84 cases had been reported from 19 different states. Among the patients, 88% were aged ≥60 years; 55% were female, and two were pregnant. Fifteen deaths have been reported. This outbreak has the highest number of deaths of any U.S. foodborne outbreak since a listeriosis outbreak in 1998.