Listeriosis, 2006

Seven cases of listeriosis were reported during 2006. Five case-patients were hospitalized, and one died. The median age of case-patients was 63 years (range, 53 to 81 years). Four had Listeria monocytogenes isolated from blood, two from stool, and one from a liver cyst. Two of the cases were identified as part of an investigation of a foodborne outbreak of febrile gastroenteritis. All five of the non-outbreak cases had underlying medical conditions.

The seven cases reported in 2006 is similar to the median annual number of cases reported from 2000 through 2005 (median, 6 cases; range, 4 to 15).

A foodborne outbreak of febrile gastroenteritis caused by L. monocytogenes was associated with eating at a restaurant in Dakota County in June. Two cases reported diarrhea, abdominal cramping, chills, fever (101º F and 103.4º F), and severe body aches 25 hours and 30 hours after eating together at the restaurant. The duration of illness for both cases was greater than 7 days. Stool specimens for both cases were positive for L. monocytogenes, and the isolates had indistinguishable PFGE patterns. Both cases reported eating chicken taco salad. A specific ingredient was not implicated. Although environmental samples at the restaurant tested negative for Listeria, numerous critical food-handling violations were noted at the restaurant which likely contributed to the outbreak.

Elderly persons, immunocompromised individuals, pregnant women, and neonates are at highest risk for acquiring listeriosis. Listeriosis generally manifests as meningoencephalitis and/or septicemia in neonates and adults. Pregnant women may experience a mild febrile illness, abortion, premature delivery, or stillbirth. In healthy adults and children, symptoms usually are mild or absent. L. monocytogenes can multiply in refrigerated foods.

• For up to date information see>> Listeriosis (Listeria)
• Full issue>> Annual Summary of Communicable Diseases Reported to the Minnesota Department of Health, 2006