Spatial dynamics of meningococcal meningitis in Niger: observed patterns in comparison with measles

• Published in: Epidemiology and infection 2012-08, Vol.140 (8), p.1356-1365
• Main Authors: BHARTI, N., BROUTIN, H., GRAIS, R. F., FERRARI, M. J., DJIBO, A., TATEM, A. J., GRENFELL, B. T.
• Format: Article
• Language: English
• Subjects: Asymptomatic; Bacterial diseases; Bacterial diseases of the nervous system. Bacterial myositis; Bacterial meningitis; Bacteriology; Biological and medical sciences; Climate; Disease; Disease outbreaks; Disease transmission; Dry season; Epidemics; Epidemiology; Fundamental and applied biological sciences. Psychology; Human bacterial diseases; Humans; Humidity; Incidence; Infections; Infectious diseases; Measles; Measles - epidemiology; Medical sciences; Meningitis; Meningitis, Meningococcal - complications; Meningitis, Meningococcal - epidemiology; Meningococcal meningitis; Microbiology; Neisseria meningitidis; Niger - epidemiology; Population Dynamics; Population size; Public health; Rain; Seasons; Surveillance; Time Factors; Vaccination; Vaccines
• ISSN: 0950-2688; 1469-4409
• DOI: 10.1017/S0950268811002032

Throughout the African meningitis belt, meningococcal meningitis outbreaks occur only during the dry season. Measles in Niger exhibits similar seasonality, where increased population density during the dry season probably escalates measles transmission. Because meningococcal meningitis and measles are both directly transmitted, we propose that host aggregation also impacts the transmission of meningococcal meningitis. Although climate affects broad meningococcal meningitis seasonality, we focus on the less examined role of human density at a finer spatial scale. By analysing spatial patterns of suspected cases of meningococcal meningitis, we show fewer absences of suspected cases in districts along primary roads, similar to measles fadeouts in the same Nigerien metapopulation. We further show that, following periods during no suspected cases, districts with high reappearance rates of meningococcal meningitis also have high measles reintroduction rates. Despite many biological and epidemiological differences, similar seasonal and spatial patterns emerge from the dynamics of both diseases. This analysis enhances our understanding of spatial patterns and disease transmission and suggests hotspots for infection and potential target areas for meningococcal meningitis surveillance and intervention.