Dr Muiris Houston, Medical Correspondent, outlines the clinical features and treatment of meningitis infection and explains the characteristics of the meningococcus bacteria.
Bacterial meningitis is caused by a number of organisms of which meningococcus is the most virulent.
The meningococcus bug is also called Neisseria meningitidis. There are three subgroups of meningococci: Groups A, B and C.
Group A causes regular epidemics in sub-Saharan Africa. In this State, Group B accounts for 60 per cent of cases, with Group C meningococcus causing about 40 per cent.
Under-twos have the highest incidence of meningococcal C infection. The Republic has the highest incidence of meningitis in Europe.
There were 165 cases of meningoccocal Group C disease in the State between July 1999 and June 2000. One in 10 people who contract meningitis C die from the infection.
The UK experience suggests we should observe a 75 per cent reduction in meningitis C cases after the initial immunisation programme. The uptake of vaccine amongst under-twos has been good. But there is some concern that the other target group - teenagers and college students - have not been availing of the vaccine to the same degree.
Clinical features: Regardless of the particular type of bacteria causing the meningitis, the classical features of the disease include headache, neck stiffness, photophobia or dislike of light, vomiting and fever. However, in younger children, the signs may be far less specific and may include lethargy, irritability, poor feeding and convulsions.
The classical rash of meningitis is actually caused by the infection spreading to the bloodstream. This condition is called septicaemia and leads to the appearance of a purple pinprick rash on the skin. Untreated, this spreads rapidly to form more confluent areas of discolouration.
When pressed upon, with a clean glass, the rash does not disappear. The appearance of a septicaemic rash indicates that the meningococcus bug is to blame for the infection.
Treatment: is with intravenous antibiotics, given on suspicion of meningitis and preferably before hospital admission. Close household and school contacts of the patient with proven meningococcal meningitis are given an oral dose of an antibiotic called Rifampicin to protect them from the bug.