Surveillance of meningococcal infections and other forms of purulent meningitis: a 4-year study in the USSR.

The laboratory examination, by microscopic or bacteriological methods and by counterimmunoelectrophoresis, of CSF and blood from 2653 patients with purulent bacterial meningitis, including those with clinically diagnosed meningococcal infection, was carried out between June 1980 and June 1984. The results showed three main etiological agents: meningococci (79.9%), pneumococci (10.8%) and Haemophilus influenzae type b (5.25%). Out of 488 Neisseria meningitidis strains isolated from the CSF or blood, 58.2% belonged to serogroup A, 17.2% to serogroup B, and 14% to serogroup C; infection due to the B serogroup reached nearly 59% among children in 1984. Serotypes were determined in 131 out of 151 strains of Streptococcus pneumoniae and the most frequent were types 1, 19 and 3; type 34, which was isolated from 4 patients, is not a component of the pneumococcal vaccine. The age groups at high risk were children under 5 years old (for meningococcal infection), adults and babies in the first year (pneumococcal meningitis), and children under 3 years, especially between 6 months and 2 years old (H.influenzae type b infection).