Epidemics in Africa

Studies show that

  • Epidemic meningitis has been present on the African continent for about 100 years
  • The disease prevails in the sub-Saharan meningitis belt
  • Epidemics there occur in the dry season (December to June), they last for two to three seasons, dying out during the intervening rainy season
  • Epidemics usually take place in irregular cycles every 5-12 years but may be more frequent and irregular in regions with expensive communication and mixing of population
  • Serogroup A meningococci account for about 80-85 percent of all cases
  • In 2002 there was a major outbreak of meningococcal meningitis in Burkina Faso with about 80 percent of cases due to serogroup W135.

The size of these epidemics can be enormous. In major African epidemics, the attack rate ranges from 100 to 800 per 100,000 population, but individual communities have reported rates as high as 1/100. In comparison, the average attack rate in industrialized nations is around 1 to 3/100,000 of the population.

Between 1988 and 1997, 704,000 cases and more than 100,000 deaths were reported in Africa, some 20,000 occurring in 1996, the largest epidemic year ever recorded. Between 1998 and 2002, African countries within the meningitis belt reported more than 224,000 new cases of meningococcal meningitis to the World Health Organization. However, the true disease burden is likely to be greater because routine reporting systems break down during epidemics. In addition, many people die before reaching a health center and thus remain unrecorded in official statistics.

While all the risk factors for meningococcal outbreaks in Africa are not understood, several conditions have been associated with the development of epidemics in the meningitis belt. They include:

  • Medical conditions: immunological susceptibility of the population,
  • Demographic conditions: travel and large population displacements,
  • Socioeconomic conditions: poor living conditions and overcrowded housing, and
  • Climatic conditions: drought and dust storms.

Photo Credit: Benoît Lange (left); Benoît Lange (right)

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