RESUMO
In 2015, Niger reported the largest epidemic of Neisseria meningitidis serogroup C (NmC) meningitis in sub-Saharan Africa. The NmC epidemic coincided with serogroup W (NmW) cases during the epidemic season, resulting in a total of 9,367 meningococcal cases through June 2015. To clarify the phylogenetic association, genetic evolution, and antibiotic determinants of the meningococcal strains in Niger, we sequenced the genomes of 102 isolates from this epidemic, comprising 81 NmC and 21 NmW isolates. The genomes of 82 isolates were completed, and all 102 were included in the analysis. All NmC isolates had sequence type 10217, which caused the outbreaks in Nigeria during 2013-2014 and for which a clonal complex has not yet been defined. The NmC isolates from Niger were substantially different from other NmC isolates collected globally. All NmW isolates belonged to clonal complex 11 and were closely related to the isolates causing recent outbreaks in Africa.
Assuntos
Genoma Bacteriano , Meningite Meningocócica/microbiologia , Neisseria meningitidis Sorogrupo C/genética , Neisseria meningitidis/genética , Antígenos de Bactérias/genética , Doenças Transmissíveis Emergentes , DNA Bacteriano , Farmacorresistência Bacteriana/genética , Epidemias , Variação Genética , Humanos , Meningite Meningocócica/epidemiologia , Tipagem Molecular , Neisseria meningitidis/isolamento & purificação , Neisseria meningitidis Sorogrupo C/isolamento & purificação , Níger/epidemiologia , Filogenia , Análise de Sequência de DNA , SorotipagemRESUMO
BACKGROUND: To combat Neisseria meningitidis serogroup A epidemics in the meningitis belt of sub-Saharan Africa, a meningococcal serogroup A conjugate vaccine (MACV) has been progressively rolled out since 2010. We report the first meningitis epidemic in Niger since the nationwide introduction of MACV. METHODS: We compiled and analysed nationwide case-based meningitis surveillance data in Niger. Cases were confirmed by culture or direct real-time PCR, or both, of cerebrospinal fluid specimens, and whole-genome sequencing was used to characterise isolates. Information on vaccination campaigns was collected by the Niger Ministry of Health and WHO. FINDINGS: From Jan 1 to June 30, 2015, 9367 suspected meningitis cases and 549 deaths were reported in Niger. Among 4301 cerebrospinal fluid specimens tested, 1603 (37·3%) were positive for a bacterial pathogen, including 1147 (71·5%) that were positive for N meningitidis serogroup C (NmC). Whole-genome sequencing of 77 NmC isolates revealed the strain to be ST-10217. Although vaccination campaigns were limited in scope because of a global vaccine shortage, 1·4 million people were vaccinated from March to June, 2015. INTERPRETATION: This epidemic represents the largest global NmC outbreak so far and shows the continued threat of N meningitidis in sub-Saharan Africa. The risk of further regional expansion of this novel clone highlights the need for continued strengthening of case-based surveillance. The availability of an affordable, multivalent conjugate vaccine may be important in future epidemic response. FUNDING: MenAfriNet consortium, a partnership between the US Centers for Disease Control and Prevention, WHO, and Agence de Médecine Preventive, through a grant from the Bill & Melinda Gates Foundation.