Four cases of listeriosis were reported during 2002; all cases occurred from September through December. All four case-patients were hospitalized, and one case was fatal. None of the cases was associated with a recognized outbreak. Ages of the case-patients were 47, 64, 70, and 73 years. All four had underlying medical conditions, including two with kidney transplants, one who required dialysis, and one with diabetes.
The number of reported listeriosis cases has declined recently, from 19 cases in 1999 to four cases in 2002. The mean number of cases reported annually from 1996 to 2002 was 11 (range, four to 19 cases).
Elderly persons, pregnant women, neonates, and immunocompromised individuals 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. Listeria 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.