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Serogroup X meningococci (NmX) historically have caused sporadic and clustered meningitis cases in sub-Saharan Africa. To study recent NmX epidemiology, we analyzed data from population-based, sentinel and passive surveillance, and outbreak investigations of bacterial meningitis in Togo and Burkina Faso during 2006-2010. Cerebrospinal fluid specimens were analyzed by PCR. In Togo during 2006-2009, NmX accounted for 16% of the 702 confirmed bacterial meningitis cases. Kozah district experienced an NmX outbreak in March 2007 with an NmX seasonal cumulative incidence of 33/100,000. In Burkina Faso during 2007-2010, NmX accounted for 7% of the 778 confirmed bacterial meningitis cases, with an increase from 2009 to 2010 (4% to 35% of all confirmed cases, respectively). In 2010, NmX epidemics occurred in northern and central regions of Burkina Faso; the highest district cumulative incidence of NmX was estimated as 130/100,000 during March-April. Although limited to a few districts, we have documented NmX meningitis epidemics occurring with a seasonal incidence previously only reported in the meningitis belt for NmW135 and NmA, which argues for development of an NmX vaccine.

Background: Public health and clinical strategies for meningitis epidemics in sub-Saharan Africa usually assume that Neisseria meningitidis infection causes most disease., Methods: During 24 months from 2002 to 2005, we collected clinical and laboratory information for suspected acute bacterial meningitis cases from 3 districts in Burkina Faso. Streptococcus pneumoniae was identified by culture, polymerase chain reaction, or antigen detection in cerebrospinal fluid. Pneumococcal genotyping was performed on strains using multilocus variable-number tandem repeat typing and multilocus sequence typing., Results: Samples of cerebrospinal fluid were collected from 1686 persons; 249 (15%) had S. pneumoniae identified (annual incidence, 14 cases per 100,000 persons). Of these patients, 115 (46%) died, making S. pneumoniae the most commonly identified organism and responsible for two-thirds of deaths due to bacterial meningitis. During the meningitis epidemic season, an average of 38 cases of S. pneumoniae infection were identified each month, compared with an average of 8.7 cases during other months. Of 48 pneumococci that were tested, 21 (44%) were identified as serotype 1, and the remaining 27 (56%) were identified as 15 different serogroups and/or serotypes. Both serotype 1 and other serogroups and/or serotypes were seasonal. The genotypes of serotype 1 isolates were closely related but diversified over the study period and were similar to, but not identical to, the predominant genotypes found previously in Ghana., Conclusions: Intervention strategies during the epidemic season in Burkina Faso (and perhaps elsewhere) must now account for pneumococcal meningitis occurring in an epidemic pattern similar to meningococcal meningitis. Although a serotype 1 clone was commonly isolated, over half of the cases were caused by other serogroups and/or serotypes, and genetic diversification increased over a relatively short period.