Issue date: 22 June 2004
Joint press release with Royal Holloway, University of London

Meningococcal meningitis outbreaks explained by mathematics

Outbreaks of meningococcal meningitis depend on small differences in the pathogenicity of different bacterial strains, a new report indicates. About 5 per cent - 25 per cent of individuals carry meningococcal bacteria but do not have meningococcal disease. Only about 0.01 per cent of those carrying the bacteria actually contract meningitis or septicaemia.

Previous research has shown that meningococci vary in the ability to cause the disease depending on strain type. Approximately ten hyperinvasive strains are responsible for the majority of recent meningococcal disease outbreaks.

The research team, funded by The Wellcome Trust and consisting of Vincent Jansen and Nico Stollenwerk from Royal Holloway - University of London, and co-investigator Martin Maiden, University of Oxford, developed a mathematical model to determine whether the diversity of strains is related to outbreaks of meningococcal disease. The study shows that large outbreaks occur if meningococcal strains with a slightly higher than average disease-causing potential appear in the population.

Paradoxically, strains that have only a weak potential to cause meningococcal disease are most likely to cause large outbreaks. This has implications for the control and management of meningococcal disease outbreaks.

Media contacts
Mark Anderson
Wellcome Trust Media Office
Tel: 020 7611 8612
E-mail: m.anderson@wellcome.ac.uk

Vincent A A Jansen
Royal Holloway - University of London
Tel: +44 (0)1784 443179
Fax: +44 (0)1784 470756
E-mail: vincent.jansen@rhul.ac.uk

Martin C J Maiden
University of Oxford
Tel: +44 (0)1865-271284
Fax: +44 (0)1865 271284
E-mail martin.maiden@zoo.ox.ac.uk

Christine Long
Royal Holloway, University of London, Press Office
Press and PR Officer
Tel: +44 (0)1784 443967
E-mail christine.long@rhul.ac.uk

Vicky Cousins
Assistant Press and Communications Officer
Tel: +44 (0)1784 414480
E-mail victoria.cousins@rhul.ac.uk

Note to editors

1. 'Diversity in pathogenicity can cause outbreaks of meningococcal disease' by Nico Stollenwerk, Martin C J Maiden and Vincent A A Jansen. Proceedings of the National Academy of Sciences USA, Online Early Edition.

2. The Wellcome Trust is an independent research funding charity established in 1936 under the will of the tropical medicine pioneer Sir Henry Wellcome. The Trust's mission is to foster and promote research with the aim of improving human and animal health and it currently spends over £400 million per annum.

3. Project team
Vincent A A Jansen is Professor of Mathematical Biology at the School of Biological Sciences, Royal Holloway - University of London.

Martin C J Maiden is a Wellcome Trust Senior Research Fellow at the Department of Zoology, University of Oxford.

Nico Stollenwerk is a postdoctoral research assistant at the School of Biological Sciences, Royal Holloway - University of London.