Listeria (Listeriosis)

Multistate Outbreak of Listeriosis Linked to Rocky Ford Cantaloupes

Persons infected with the outbreak strain of Listeria monocytogenes, by date of illness onset*

Chart showing bar graph indicating numbers of people infected with the outbreak strains of Listeria monocytogenes, by date of illness onset

Onset data not currently available for all persons with reported illness.

*n=16 for whom information on illness onset was reported as of 9/13/2011

Among persons for whom information is available, illnesses began on or after August 15, 2011. Ages range from 38 to 96 years, with a median age of 83 years old. Most ill persons are over 60 years old or have health conditions that weaken the immune system. Sixty-nine percent of ill persons are female. Among the 15 with information available, all were hospitalized. One death has been reported.

The outbreak can be visually described with a chart showing the number of persons who became ill each day. This chart is called an epidemic curve or epi curve. Illnesses that occurred after August 28, 2011, might not be reported yet due to the time it takes between when a person becomes ill and when the illness is reported. Please see the description of the steps in a foodborne outbreak investigation for more details.