Lessons from meningococcal carriage studies

Authors

  • Dominique A. Caugant,

    1. Department of Bacteriology and Immunology, Division of Infectious Disease Control, Norwegian Institute of Public Health, Oslo, Norway
    2. Institute of Oral Biology, University of Oslo, Oslo, Norway
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  • Georgina Tzanakaki,

    1. Meningitis National Reference Laboratory, National School of Public Health, Athens, Greece
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  • Paula Kriz

    1. National Reference Laboratory for Meningococcal Infections, National Institute of Public Health, Prague, Czech Republic
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  • Editor: Matthias Frosch

Correspondence: Dominique A. Caugant, Department of Bacteriology and Immunology, Division of Infectious Disease Control, Norwegian Institute of Public Health, PO Box 4404 Nydalen, NO-0403 Oslo, Norway. Tel.: +47 22 04 23 11; fax+47 22 04 25 18; e-mail: dominique.caugant@fhi.no

Abstract

Neisseria meningitidis, an obligate commensal of humans, normally colonizes the mucosa of the upper respiratory tract without affecting the host, a phenomenon known as carriage. In Europe, as much as 35% of young adults are carriers at a given time. Recent studies using molecular methods for clone identification have demonstrated the extensive genetic diversity of the strains isolated from carriers, in comparison with a limited number of hypervirulent strains associated with invasive disease. Published studies and new data generated through the framework of the EU-MenNet clearly indicated significant differences in pathogenicity between meningococcal clones and in the distribution of multilocus sequence types among isolates from asymptomatic carriers among European countries; simultaneous carriage of more than one meningococcal strain in the throat is rare, but occasionally occurs; and the commensal association of particular clones with a host is a long-term relationship, often lasting several months. Further investigations of the carrier state are warranted to improve our understanding of the epidemiology and pathogenesis of meningococcal disease, as well as to support the introduction and to measure the impact of mass vaccination.

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