MENINGOCOCCAL DISEASE IN AFRICA

Neisseria meningitidis (the meningococcus) is responsible for endemic and epidemic meningococcal disease in Africa. Meningococci are placed into 12 serogroups based on their capsular polysaccharide antigens. Gr oup-B meningococci are responsible for sporadic endemic disease. In th e meningitis belt of sub-Saharan Africa, the large spreading epidemics which occur every 5-10 years are usually caused by group-A meningococ ci, with attack rates of 400-500/100 000 population. In the last epide mic, infection spread from the original meningitis belt to Kenya, Ugan da, Rwanda, Zambia and Tanzania. Most cases of meningococcal disease a re of meningitis and meningococcal septicaemia is a rare presentation except in South Africa. It is important to exclude meningococcal septi caemia since this carries the highest mortality (up to 75%). Treatment involves intravenous chloramphenicol (or intramuscular, oily chloramp henicol), a drug which is preferable to penicillin because penicillin- resistant meningococci have already emerged in Africa. Dexamethasone t reatment of meningococcal meningitis is unproven and may even be delet erious in developing countries. Prevention of epidemic meningococcal d isease could be achieved by mass vaccination with protein-conjugate, g roup-A and -C polysaccharides, but these new vaccines are likely to be expensive.