The belt was first proposed by Léon Lapeyssonnie of the World Health Organization (WHO) in 1963. Lapeyssonnie noticed that the disease occurred in areas receiving 300–1,100mm of mean annual rainfall, which is the case in sub-Saharan Africa.[1] The intercontinental spread of meningitis has also been traced to South Asia, brought by those making the Hajj, a pilgrimage to Saudi Arabia, in 1987, leading to epidemics in Nepal, Saudi Arabia, and Chad.[2]
The most affected countries in the region are Burkina Faso, Chad, Ethiopia, and Niger. Burkina Faso, Ethiopia, and Niger were accountable for 65% of all cases in Africa. In major epidemics, the attack rate range is 100 to 800 people per 100,000. However, communities can have attack rates as high as 1000 per 100,000. During these epidemics, young children have the highest attack rates.[4] More than 90,000 cases were reported in the belt in 2009, in comparison, less than 800 cases were reported in the United States[5] in 2011.
Epidemiology
Neisseria meningitidis is found in other parts of the world as well, but the highest rates occur in the “meningitis belt.” Meningococcal disease is persistently high in this region. Large epidemics occur every 5–12 years, typically during the dry season (December–June). Incidence of the disease declines from May to June in the more humid weather.[6] Other factors contributing to the sustained transmission of meningococcal disease include dust, other respiratory viruses that co-circulate, as well as close social contact.[7]
Historically, 90% of outbreaks in the meningitis belt were primarily due to Neisseria meningitidisserogroup A (NmA).[8] However, a monovalent serogroup A meningococcal conjugate vaccine (MenAfriVac) was introduced in the region in 2010. Since then, meningococcal outbreaks in the meningitis belt have primarily been due to serogroups C and W. A few serogroup X outbreaks have also been reported.[9]
In the African meningitis belt, the WHO defines a meningococcal epidemic as at least 100 cases per 100,000 inhabitants in a year.[10] At its peak, the incidence of meningococcal disease has reached rates of up to 1,000 cases per 100,000 inhabitants, such as during the epidemics of 1996 and 2000–2001.[11] In the belt, fatality from NmA disease has been estimated at 10–15%, although higher rates have been seen in some settings.[12] Around 10–20% of survivors of meningococcal meningitis are left with permanent neuropsychological conditions such as hearing loss, vision loss, epilepsy, or other neurological disorders. Young children are particularly vulnerable due to immaturity in their immune systems, which contributes to the disproportionate burden of the disease in Africa due to its young population.[13]
The Meningitis Vaccine Project was conceived in 2001 as an effort to stop the spread of meningitis in this region.[14]
References
↑ Lapeyssonnie, L. (November 1968). "[Comparative epidemiologic study of meningococcic cerebrospinal meningitis in temperate regions and in the meningitis belt in Africa. Attempt at synthesis]". Médecine Tropicale: Revue du Corps de Santé Colonial. 28 (6): 709–720. ISSN0025-682X. PMID5739513.
↑ Murray, Patrick R.; Rosenthal, Ken S.; Pfaller, Michael A. (28 October 2015). Medical microbiology (8thed.). Philadelphia, PA. ISBN9780323299565. OCLC914223501.{{cite book}}: CS1 maint: location missing publisher (link)
↑ Greenwood, B. M.; Bradley, A. K.; Smith, A. W.; Wall, R. A. (1987). "Mortality from meningococcal disease during an epidemic in The Gambia, West Africa". Transactions of the Royal Society of Tropical Medicine and Hygiene. 81 (4): 536–538. doi:10.1016/0035-9203(87)90397-x. ISSN0035-9203. PMID3445333.
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