Molecular surveillance of meningococcal meningitis in Africa.

Analysis of meningococcal strains recovered from outbreaks and epidemics in the African meningitis belt, using molecular methods, has demonstrated for nearly 20 years the dominance among serogroup A organisms of a single clone complex, the sequence type 5 (ST-5) complex. However, a shift was observed since the mid-1990s when ST-5 gradually was replaced by ST-7 in all countries of the region. Since 2001, outbreaks caused by serogroup W135 strains belonging to the ST-11 complex became an additional problem. Monitoring of the clones responsible for meningococcal disease provides important insights on the biology and epidemiology of this most serious pathogen.