It strikes suddenly and can kill within hours. Meningitis is a word that strikes fear into the hearts of parents. That fear is sharply focused following the tragic death of a young Monaghan teenager and the hospitalisation of three other boys from the town.
Doctors realise that there is a fine balance between warning parents to be vigilant for the signs of meningitis, given the seeming innocuousness of the early symptoms, and causing undue alarm. Nine out of 10 people who get meningitis will survive, but it is those who die who stick in the public mind.
Meningitis is inflammation of the membrane lining the brain and spinal cord and is caused by either viral or bacterial infection. It can affect anyone, although babies, teenagers and those in their early 20s are more susceptible to it.
There are two main forms, bacterial and viral. Of the two, bacterial meningitis is by far the worst and is often accompanied by septicaemia (blood-poisoning).
At any one time 10 per cent of the population will carry the bacteria which cause the most common form of meningitis. This rises to 25 per cent in the young adult population. The meningococcus organism is carried in the back of the throat. While this bug is common, the disease is rare. When someone gets meningitis the bug has broken through the protective mucosal tissue which lines the inner surface of the nose, mouth and throat. It is not known why this occurs.
Once in the bloodstream the bacteria are free to circulate and cause damage. Without antibiotics they can easily kill. The bacteria are spread by droplet transmission, that is, sneezing, coughing or kissing.
Detailed figures in Ireland are not available over a number of years, making it difficult to study the long-term progress of the disease. It is believed that meningitis goes in cycles from 10 to 15 years and that there are peaks and troughs during that cycle.
In Ireland the mortality rate is up to 10 per cent from meningitis. There has been an almost threefold increase in the past five years. In 1993, 203 reports of bacterial meningitis were notified, rising to 241 in 1994, 382 in 1995 and 410 in 1996. Up to November of last year there were 447 reported cases, 67 more than for the same period in the previous year.
Twenty-eight people died in 1995, 15 in 1996 and 30 up to November of last year. The death of the Monaghan teenager was the first in 1998.
The Eastern Health Board has had particularly high rates, with 169 cases and nine deaths notified in 1997. This compares with 144 cases and six deaths in 1996.
Dr Jerry Fogarty, a specialist in public health medicine with the Western Health Board, who has done research in the area, explained that the incidence of the disease had increased over the years, but notification had improved. The death rate, he said, had remained fairly constant. Now it is one of the best-notified conditions in the State.
"The bug is very common, but the disease is extremely rare. Obviously, it is frightening because it occurs so quickly and because people who die were previously very healthy. Parents often wonder if they could have done more, but the early stages are very difficult to distinguish as meningitis, even for doctors. It looks like flu, especially at this time of year. Some people with meningitis will die regardless of what is done for them medically", Dr Fogarty said.
He explained that most of the disease occurs in children in the first two years of life. There is a further increase in the incidence among young people aged between 15 and 20, and occasionally older people are affected.
Meningitis peaks usually in the first quarter of the year, and about half of the cases occur in the period from December to March.
A working group on bacterial meningitis, set up by the Minister for Health, reported last year, making a number of recommendations. These included a recommendation that preventive antibiotics be given to close contacts of confirmed or suspected cases of bacterial meningitis as soon as there is notification of a case. The risk is highest seven days after a case. The antibiotic is given to protect the individual and close contacts.
Close contacts are defined as those living in the same house, including baby-minders, those who may have been in the same creche or those who may have kissed the patient on the mouth.
Antibiotics are not considered necessary for classmates of a student who has got meningitis unless there are two or more cases of the same strain in the school during the same term. If the cases occur in the same class, all students and staff should receive antibiotics.
There is no vaccine available for meningococcal meningitis type B, the commonest type in Ireland. It is responsible for 55 per cent of cases. It is expected that it will be at least 10 years before a vaccine is available. A preventive vaccine is available for type A meningitis and is recommended for those travelling to Africa. A vaccine exists for type C, but it is not routinely available.
There is a difficulty in Ireland with the reporting of meningitis statistics because up to now the routinely-reported figures do not provide the quality of information needed to describe accurately the epidemiology of the infections. Figures from the Department of Health include all cases initially reported as meningitis but make no distinction between what strain - A, B or C - of the organism may be involved.
This should improve with the work being carried out by the National Meningococcal Reference Laboratory in Temple Street Hospital, Dublin. Laboratories throughout the Republic are required to send a sample from all cases of suspected meningitis for testing so that the strain can be specifically identified.
Those who have concerns about meningitis may contact the Meningitis Research Foundation, which will send out literature explaining the symptoms. Its telephone number is (01) 836-6347.