The rise and fall of epidemic Neisseria meningitidis serogroup W135 meningitis in Burkina Faso, 2002-2005.
BACKGROUND
During the period 2001-2002, Burkina Faso reported its first meningitis epidemic due to Neisseria meningitidis (Nm) serogroup W135, prompting concerns that this serogroup would persist as a cause of epidemic disease.


METHODS
During the period 2002-2005, hospital- and population-based surveillances were conducted in 3 districts in Burkina Faso. Etiology was determined by culture, polymerase chain reaction (PCR), and latex agglutination. Reference laboratories determined phenotype and genotype.


RESULTS
Of 2004 subjects who received a lumbar puncture, 265 were identified as having Nm, including 93 who had Nm serogroup A (NmA) and 146 who had Nm serogroup W135 (NmW135). Over the study period, the proportion of cases due to NmW135 decreased by >75%, primarily because of decreased occurrence among young children and in a single district. During peak epidemic months, the annualized incidence of NmW135 decreased from 146 cases to <1 case per 100,000 population. All but 2 NmW135 isolates were phenotype W135:2a:P1.5,2 (sequence type [ST]-11 clonal complex). All NmA isolates were phenotype A:4:P1-9 (ST-2859 of the ST-5 clonal complex). We identified 1 isolate from serogroup Y (ST-11 clonal complex), 1 isolate from serogroup X that was similar to strains previously associated with epidemic disease, and 1 isolate from serogroup W135 of the newly described ST-4375 complex.


CONCLUSIONS
For unknown reasons, serogroup W135 achieved epidemic status, primarily among young children, and then largely disappeared over a short time period. The continued circulation of multiple strains with epidemic potential emphasizes the need for ongoing surveillance and the potential benefit of vaccines that are protective across serogroups.
Traoré
Yves
Y
Université de Ouagadougou.
Njanpop-Lafourcade
Berthe-Marie
BM
Adjogble
Kokou-Louis-Sewonou
KL
Lourd
Mathilde
M
Yaro
Seydou
S
Nacro
Boubacar
B
Drabo
Aly
A
Parent du Châtelet
Isabelle
I
Mueller
Judith E
JE
Taha
Muhamed-Kheir
MK
Borrow
Ray
R
Nicolas
Pierre
P
Alonso
Jean-Michel
JM
Gessner
Bradford D
BD
D000293:Adolescent; D000328:Adult; D002050:Burkina Faso / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D004196:Disease Outbreaks; D006801:Humans; D007223:Infant; D008585:Meningitis, Meningococcal / Q000453:epidemiology* / Q000517:prevention & control; D022401:Meningococcal Vaccines / Q000008:administration & dosage; D038582:Neisseria meningitidis, Serogroup W-135 / Q000145:classification / Q000302:isolation & purification*; D012703:Serotyping
D022401:Meningococcal Vaccines