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Meningococcal disease in Africa
1Department of Medical Microbiology and Genito-Urinary Medicine, Liverpool, U.K. cahmm@liv.ac.uk
Abstract:
Neisseria meningitidis (the meningococcus) is responsible for endemic and meningococcal disease in Africa. Meningococci are placed into 12 serogroups based on their capsular polysaccharide antigens. Group-B meningococci are responsible for sporadic endemic disease. In the meningitis belt of sub-Saharan Africa, the large spreading epidemics which occur every 5-10 years are usually caused by group-A meningococci, with attack rates of 400-500/100,000 population. In the last epidemic, infection spread from the original meningitis belt to Kenya, Uganda, Rwanda, Zambia and Tanzania. Most cases of meningococcal disease are of meningitis and meningococcal septicaemia is a rare presentation except in South Africa. It is important to exclude meningococcal septicaemia since this carries the highest mortality (up to 75%). Treatment involves intravenous chloramphenicol (or intramuscular, oily chloramphenicol), a drug which is preferable to penicillin because penicillin-resistant meningococci have already emerged in Africa. Dexamethasone treatment of meningococcal meningitis is unproven and may even be deleterious in developing countries. Prevention of epidemic meningococcal disease could be achieved by mass vaccination with protein-conjugate, group-A and -C polysaccharides, but these new vaccines are likely to be expensive.
Insights
Neisseria meningitidis causes widespread epidemics in Africa, primarily group-A strains. Effective treatment requires chloramphenicol due to emerging penicillin resistance, and prevention may involve costly conjugate vaccines.
Area of Science:
- Microbiology
- Epidemiology
- Infectious Diseases
Background:
- Neisseria meningitidis (meningococcus) causes endemic and epidemic meningococcal disease globally.
- Sub-Saharan Africa's "meningitis belt" experiences devastating group-A meningococcal epidemics every 5-10 years.
- Group-B meningococci are associated with sporadic endemic disease, while group-A causes large-scale epidemics.
Purpose of the Study:
- To outline the epidemiology and clinical presentation of meningococcal disease in Africa.
- To discuss appropriate treatment strategies, considering antimicrobial resistance.
- To explore preventive measures, including vaccination.
Main Methods:
- Review of existing literature on meningococcal disease in Africa.
- Analysis of serogroup distribution and epidemic patterns.
- Evaluation of treatment options and preventive strategies.
Main Results:
- Group-A meningococci are the primary cause of major epidemics in the African meningitis belt, with high attack rates.
- Meningococcal septicaemia, though rare, has a high mortality rate (up to 75%) and requires prompt recognition.
- Penicillin-resistant meningococci have emerged in Africa, necessitating alternative treatments like chloramphenicol.
Conclusions:
- Chloramphenicol is the preferred treatment for meningococcal disease in Africa due to penicillin resistance.
- Dexamethasone's role in treating meningococcal meningitis in developing countries is uncertain and potentially harmful.
- Mass vaccination with group-A and -C polysaccharide conjugate vaccines could prevent epidemics but may be expensive.