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Populations of pharyngeal meningococci in Niger

Pierre Nicolas1, Saacou Djibo, Bernard Tenebray

  • 1Institut de Médecine Tropicale du Service de Santé des Armées (IMTSSA), WHO Collaborating Center for Reference and Research on Meningococci, BP 46, 13998 Marseille, France. nicolasp@imtssa.fr

Vaccine
|May 23, 2007
PubMed

Insights

This study identified Neisseria meningitidis carriage in Niger schoolchildren, finding NmW135 ST-2881 and Nm NG ST-192 as most common. These findings are crucial for planning meningococcal conjugate vaccine introduction in Africa.

Area of Science:

  • Microbiology
  • Epidemiology
  • Vaccinology

Background:

  • Neisseria meningitidis (Nm) lineages ST-7, ST-11, and NmW135 ST-2881 caused sporadic cases in Niger in 2003.
  • ST-7 and ST-11 were implicated in recent African meningitis belt outbreaks.

Purpose of the Study:

  • To investigate the carriage of specific Neisseria meningitidis lineages in schoolchildren in Niamey, Niger.
  • To assess the prevalence of NmW135, NmA ST-7, and other relevant Nm strains.
  • To inform the potential introduction of a Neisseria meningitidis serogroup A (NmA) conjugate vaccine.

Main Methods:

  • Collected 97 Nm isolates from 287 schoolchildren via three throat swabs.
  • Identified Nm serogroups and genotyped isolates using sequence typing (ST).

Main Results:

  • Identified 1 NmA, 34 NmW135, 8 NmY, and 54 non-groupable (NG) isolates.
  • Genotyping revealed ST-192 (59.3%) and ST-2881 (24.4%) as predominant.
  • Nm NG ST-192 and NmW135 ST-2881 were the most frequently recovered, often weakly pathogenic.

Conclusions:

  • The study identified prevalent Neisseria meningitidis strains in Niger schoolchildren.
  • Findings highlight the importance of understanding local carriage dynamics before NmA conjugate vaccine deployment.
  • Preliminary data suggests NmW135 ST-2881 and Nm NG ST-192 are key circulating strains.

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