[Neisseria meningitidis and meningitis].

Meningococcal meningitis epidemics can occur anywhere in the world. However this risk is particularly high during the dry season in the sub-Saharan zone of Africa known as the Lapeyssonnie meningitis belt. This area characterized by hyperendemicity that regularly gives rise to epidemics. Multilocus enzyme electrophoresis has made possible identification and monitoring of the progression of virulent clones of Neisseria meningitidis strains in the world. Monitoring is now possible by multilocus sequence typing and data bank on the Internet. Vaccination is a major prophylactic modality. The usefulness of plain group A plus C polysaccharide vaccines is limited because of poor effectiveness in young children who constitute the highest risk group. During epidemics, mass vaccination should be carried out as early as possible according to the state of alert defined for the area. More recent conjugate vaccines against group A and C, which are effective in young children and provide long-term protection by induction of immunologic memory, may allow routine vaccination in the future. Although clinical signs are often apparent, not all cases are diagnosed by clinical examination unless gravity is taken into account. Untreated the disease is always fatal. The only hope of survival is early institution of appropriate antimicrobial therapy (even prior to hospitalization). Several strains resistant to chloramphenicol have been reported and the number of strains with reduced sensitivity to penicillin is rising constantly. Although treatment remains feasible, the existence of resistant forms raises the need to monitor the sensitivity of meningococci using standardized of antibiograms.