Epidemiology of invasive meningococcal infections of children in Slovenia during 1993-1999

Invasive strains of Neisseria meningitidis isolated from sterile body fluids of children aged 0-14 years were intentionally collected in nine Slovenian laboratories, and sent to the laboratory of the National Institute of Public Health, Ljubljana for final evaluation. From 1993-1999 we collected 53 invasive strains from children presented in this study. The incidence rate of invasive diseases in children shows that there is a rapid fall from 4.74/100,000 in 1993 to 0.90/100,000 in 1999. Invasive diseases predominated in children in the age group 0-1 year (19.6 cases per 100,000 children); followed by the age groups 2-4 years, 5-9 years and 10-14 years. The results of serogrouping indicate that the largest proportion of meningococci isolated (90%) were group B, while 8% of isolates were group C and only 2% group Y. The serotype/serosubtype distribution shows that the most frequent serotype (excluding 19 non-typable NT strains) was serotype 22, which was expressed in 9 strains and the most frequent serosubtype (excluding 11 NST strains) was P1.5,2 found in 7 strains. The most frequently isolated strains (excluding NT/NST strains) were B:22:P1.14; B:NT:P1.5 and B:NT:P1.16. Thirty-one strains collected during 1993-1995 were analysed by multilocus enzyme electrophoresis (MEE). There were 25 electrophoretic types (ETs) among 31 strains; the strains were very heterogeneous with only four ETs being represented by more than one strain. Study shows that meningococcal disease is still endemic in Slovenia.