Meningitis - from hitchhiker to killer bug
The arm of a young child with meningococcal septicaemia.
Professor Richard Moxon, Dr Christopher Bayliss, Dr Man-Suen Chan, Ms Mary Deadman, Mr Kevin Dixon, Dr Derek Hood, Ms Anne Jäkel, Mr Gaurav Kumar, Ms Katherine Makepeace, Dr Patricia Martin, Dr Joyce Plested, Ms Gaynor Randle, Dr Wendy Sweetman and Dr Claire Wright.
University of Oxford.
Meningitis is a potentially lethal disease that frequently hits the headlines. It can be caused by several different types of bacteria that are normally present in the nose and throat of a majority of people and coexist with us without causing any problems. However, these placid hitchhikers occasionally become invasive and potential killers. Why do these bacteria turn the tables on their host and what can be done to tame the killers once they are let loose?
There were over 2000 cases of meningitis reported in the UK last year and infection can happen at any age. However, the majority of cases occur in children under 4 with a second peak in cases recorded for teenagers aged between 15 and 19 years. 'The disease meningitis causes infection and inflammation of the lining of the brain and the same bacteria can also cause septicaemia (blood poisoning)', says Richard Moxon. 'Although the infection is not highly contagious the bacteria are passed by close contact, which usually means kissing or the normal contact between people living in the same household. The bacteria cannot survive for long outside the human body.'
In the last decade successful vaccines have been introduced in the UK against Haemophilus influenzae type b, the Hib vaccine, and also against Neisseria meningitidis serogroup C, the Meningitis C vaccine. These have dramatically reduced the incidences of disease caused by these two bacteria. They do not, however, prevent disease caused by other strains of these bacteria, in particular Meningitis B. The main aim of the research at Oxford is to develop a vaccine against Neisseria meningitidis serogroup B strains of bacteria, which are currently responsible for the vast majority of cases of meningitis in the UK.
Vaccines have to be tailored specifically to each bacterium that they protect against because all bacteria 'look' different. In particular they show different structures on their surface. These surface structures are composed of a variety of molecules including proteins, lipids or sugars. Some of these structures can be modified and so appear different to the original structure.