Fifteen cases of listeriosis were reported during 2005. All 15 case-patients were hospitalized, and two died. The median age was 67 years (range, 0 to 90 years). One case was a neonate born at 28 weeks of gestation, hospitalized for 18 days; this case-patient survived. Eleven cases had Listeria monocytogenes isolated from blood, two from cerebral spinal fluid, one from joint fluid, and one from peritoneal fluid. None of the cases were associated with a recognized outbreak.
The 15 cases reported in 2005 represent a sharp increase from the five cases seen in 2004. From 2000 through 2004, the number of cases reported ranged from four to eight cases per year (median, 5 cases). The number of cases reported in 2005 is comparable to the number of cases reported during 1997-1999, when 17 to 19 cases were reported per year.
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.
Note: For up to date information see: Listeriosis (Listeria)