Meningococcal carriage within households in the African meningitis belt: A longitudinal pilot study.
OBJECTIVES
Carriers of Neisseria meningitidis are a key source of transmission. In the African meningitis belt, where risk of meningococcal disease is highest, a greater understanding of meningococcal carriage dynamics is needed.


METHODS
We randomly selected an age-stratified sample of 400 residents from 116 households in Bamako, Mali, and collected pharyngeal swabs in May 2010. A month later, we enrolled all 202 residents of 20 of these households (6 with known carriers) and collected swabs monthly for 6 months prior to MenAfriVac vaccine introduction and returned 10 months later to collect swabs monthly for 3 months. We used standard bacteriological methods to identify N. meningitidis carriers and fit hidden Markov models to assess acquisition and clearance overall and by sex and age.


RESULTS
During the cross-sectional study 5.0% of individuals (20/400) were carriers. During the longitudinal study, 73 carriage events were identified from 1422 swabs analyzed, and 16.3% of individuals (33/202) were identified as carriers at least once. The majority of isolates were non-groupable; no serogroup A carriers were identified.


CONCLUSIONS
Our results suggest that the duration of carriage with any N. meningitidis averages 2.9 months and that males and children acquire and lose carriage more frequently in an urban setting in Mali. Our study informed the design of a larger study implemented in seven countries of the African meningitis belt.
['Basta|Nicole E|NE|', 'Berthe|Abdoulaye|A|', 'Keita|Mahamadou|M|', 'Onwuchekwa|Uma|U|', 'Tamboura|Boubou|B|', 'Traore|Awa|A|', 'Hassan-King|Musa|M|', 'Manigart|Olivier|O|', 'Nascimento|Maria|M|', 'Stuart|James M|JM|', 'Trotter|Caroline|C|', 'Blake|Jayne|J|', 'Carr|Anthony D|AD|', 'Gray|Stephen J|SJ|', 'Newbold|Lynne S|LS|', 'Deng|Yangqing|Y|', 'Wolfson|Julian|J|', 'Halloran|M Elizabeth|ME|', 'Greenwood|Brian|B|', 'Borrow|Ray|R|', 'Sow|Samba O|SO|']
D000293:Adolescent D000328:Adult D002353:Carrier State D002648:Child D002675:Child, Preschool D003430:Cross-Sectional Studies D005191:Family Characteristics D005260:Female D006801:Humans D007223:Infant D008137:Longitudinal Studies D008297:Male D008302:Mali D008403:Mass Screening D008585:Meningitis, Meningococcal D008589:Meningococcal Infections D009345:Neisseria meningitidis D038381:Neisseria meningitidis, Serogroup A D010614:Pharynx D010865:Pilot Projects D055815:Young Adult
Carriers Neisseria meningitidis Meningococcal disease Mali Africa Bacterial Meningitis Epidemiology