Listeriosis, 2004

Five cases of listeriosis were reported during 2004. Four case-patients were hospitalized, but none died. None of the cases were associated with a recognized outbreak. The median age was 53 years (range, 40 to 76 years). Two case-patients had Listeria monocytogenes isolated from joint fluid or tissue. One of these two case-patients had L. monocytogenes isolated from knee tissue and fluid. This case presented with knee pain and had a history of total knee replacement 5 years earlier. The other case presented with hip pain, had L. monocytogenes isolated from hip fluid, and had a history of total hip replacement 6 years earlier. A 46-year-old case-patient with a history of alcohol dependency and mental health problems had L. monocytogenes isolated from blood. One case-patient had several underlying conditions (congestive heart failure, anemia, arthritis, and history of acute gastrointestinal bleed) and had L. monocytogenes isolated from blood. One case-patient, a 53-year-old, did not have any underlying medical conditions, and had L. monocytogenes isolated from blood and cerebrospinal fluid.

The five cases reported in 2004 continue a recent trend of decreased listeriosis reports in Minnesota. Since 2000, the number of cases reported ranged from four to eight cases per year (median, 5 cases). This is a substantial decrease from 1997-1999, when 17 to 19 cases were reported per year. Only one of 27 cases reported in Minnesota since 2000 occurred in a pregnant woman.

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. Persons at highest risk should: 1) avoid soft cheeses (e.g., feta, Brie, Camembert, blue-veined, and Mexican-style cheeses) and unpasteurized milk; 2) thoroughly heat/reheat deli meats, hot dogs, other meats, and leftovers; and 3) wash raw vegetables.

• For up to date information see>> Listeriosis
• Full issue>> Annual Summary of Communicable Diseases Reported to the Minnesota Department of Health, 2004