Feto-maternal listeriosis in Denmark 1981-1988.

We collected clinical information about 30 cases of Listeria monocytogenes infections in pregnancy, which occurred in Denmark between 1981 and 1988. The incidence of feto-maternal listeriosis was approximately one case per 100,000 live births in the early 1980s but increased to 25.3 cases per 100,000 live births in 1986. Listeriosis in Denmark occurred in two different patterns: endemic, in which the feto-maternal cases were a small proportion of the total, and epidemic: cases due to strains which were indistinguishable by phage-typing, and having a higher proportion of feto-maternal cases, as was seen in the outbreak of 1985-1987. The study group comprised 11 cases of intra-uterine death, three of maternal septicaemia without infection of the fetus and 16 cases of neonatal infection. Most neonates were ill at birth or became so within the first 24 h. The overall mortality rate among liveborn infants was 10.5% (2/19).