Clinical and Epidemiological Aspects of Listeriosis in Belgium, 1985-1990

Between January 1985 and December 1990, 233 cases of human listeriosis were reported to the Listeria Reference Centre of Belgium. Foeto-maternal infections (88 cases) and septicemia in adults (88 cases) were the most frequent clinical manifestations, followed by CNS infections (40 cases). 71.7% of the patients presented a concurrent condition which favoured the triggering of the disease. No correlation was found between the isolation of L. monocytogenes in patients and their occupation or their animal environment. The predominant serovar was 4b (70%). On the other hand, the Reference Centre also examined 1412 foodstuffs for the presence of L. monocytogenes: 16.9% (9/53) of cooked chicken products, 15.4% (73/473) of soft cheeses and 6.9% (62/886) of cooked meat products were positive (presence of L. monocytogenes in 25 g). The contamination level of these ready-to-eat foodstuffs ranged from less than 10 cfu L. monocytogenes/g. to 10(6) cfu/g. 54.1% of the isolated strains belonged to serovar 1/2a.