Meningitis in Other Countries

Bacterial Meningitis in Other Countries

Many countries suffer from endemic meningococcal disease, primarily in children under the age of five, at an annual attack rate of around 1 to 3 per 100,000 of the population. Some of these countries, mostly in the developing world, suffer from repeated epidemics of meningitis.

In temperate regions the number of cases increases in winter and spring. Serogroups B and C together account for a large majority of cases in Europe and the Americas. Several local outbreaks due to N. meningitidis serogroup C have been reported in Canada and the U.S. (1992-93) and in Spain (1995-97). Major African epidemics are associated with N. meningitidis serogroup A, which is usually the cause of meningococcal disease in Asia.

There is increasing evidence of serogroup W-135 being associated with outbreaks of considerable size. In 2000 and 2001 several hundred pilgrims attending the Hajj in Saudi Arabia were infected with N. meningitidis W-135. Then in 2002, W-135 emerged in Burkina Faso, striking 13,000 people and killing 1,500.

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), dying out during the intervening rainy season
• Epidemics usually take place in irregular cycles every 5-12 years
• 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 W-135

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 per 100. In comparison, the average attack rate in industrialized nations is around 1 to 3 per 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. 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
• Climatic conditions: drought and dust storms

Source: Meningitis Vaccine Project