Meningitis - the Disease
Meningitis is an inflammation of the meninges (the lining of the brain and spinal cord). It can be caused by a viral or a bacterial infection. Progress can be insidious with mild symptoms, or very rapid over a few hours.
ENSURE THAT YOU BECOME FAMILIAR WITH THE SIGNS AND SYMPTOMS OF MENINGITIS, AS THIS IS A SERIOUS DISEASE REQUIRING HOSPITALISATION.
Viral meningitis
Viral meningitis occurs most often in children, and is more common in the summer. Most cases are mild, with symptoms of headache and fever. Those affected usually recover without medical treatment. Sometimes the disease progresses with further symptoms: nausea, vomiting, stiff neck, sore throat, abdominal pain, muscle pain, and dislike of light. Viral meningitis is not usually associated with septicaemia. Antibiotics are ineffective against viruses.
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Entero viruses live in the cells lining the intestine, nose and throat. Out of 80 different known types, the main ones are cocksackie and echo virus.
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Mumps and measles viruses may rarely cause some cases of meningitis.
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Herpes viruses may cause meningitis.
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Arboviruses normally affect birds or rodents, and are carried by mosquitoes or ticks (e.g. Japanese encephalitis - see No Nonsense Travel Vaccine Handbook).
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Good hand washing and a strong immune system are normally adequate protection against viral meningitis.
Meningococcal meningitis
This is a bacterial infection with Neisseria meningitidis. Infection with this bacteria is uncommon, but is the most common cause of bacterial meningitis in the UK (approximately 4 in 100,000 per year). Children under 1 year (followed by those aged 1 to 5) are most at risk, followed by teenagers and young adults. Meningococcal bacteria live harmlessly in the nose and throats of about 1 in 4 people. The bacteria do not survive outside of the body. Close contact is needed to pass it on to others, such as prolonged kissing or coughing and sneezing near to others. Rarely, it can cause septicaemia. Most cases of meningococcal meningitis are isolated cases: the risk of others catching it are low, as many people are carriers and have natural immunity. There is a marked seasonal variation in meningococcal disease, with peak levels in the winter months declining to low levels by late summer.
Meningococcal bacteria can be divided into the following groups:
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Groups B & C. There is no vaccine for meningococcal meningitis B. The main bacteria are the meningococci which can also cause septicaemia (blood poisoning). Prior to the introduction of the meningitis C vaccine, the group C disease accounted for 40% of meningococcal meningitis. Now it is less than 10%, with group B (the most severe form) accounting for 80% [ref: NHS immunisation website] . Evidence exists that since the introduction of mass HIB vaccination in 1990, there has been increased proliferation of meningococcal B meningitis. Children between the ages of 5 and 15 years have virtually no risk of contracting meningitis C. The greatest cluster of meningitis C infection is found in young people aged between 15 and 20. Overall, there were 150 deaths from meningitis C during 1998/99, from 1,500 diagnosed cases.
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Group A is the commonest in the world, but confined to certain tropical countries.
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Groups Y & W135 are rare in UK. See No Nonsense Travel Vaccine Handbook .
Pneumococcal meningitis
The bacterial strain Strepococcus pneumoniae is known to cause approximately 100,000 cases of meningitis, septicaemia, pneumonia, ear infections and sinusitis each year in children under 5 in the UK . Up to 60% of people carry pneumococcal bacteria harmlessly in the nasal passages and throat. These bacteria will only cause illness if the immune system is compromised. It can be spread by sneezing, coughing and touch. Antibiotics can be effective on some of the 90 known strains of pneumococcal infection, in the early stages; but more and more they are becoming immune to antibiotics. For more information, see page on pneumococcal vaccines.
Haemophilus Influenzae Type B
The other bacteria often associated with meningitis is Haemophilus Influenzae Type B: this is the target for the Hib vaccine. Hib disease is rare in children under 3 months, as they are usually protected by maternal antibodies. It rises rapidly to a peak at 10 months, and then declines up to the age of 4 years, after which time Hib is uncommon because children have already acquired natural antibodies to the disease.
Haemophilus influenzae bacterial infections occur frequently in childhood, accounting for a large percentage of common sinus, throat and ear infections. They generally resolve without treatment. One strain of the Haemophilus baccillus (type B) can invade the body causing inflammation of the membranes surrounding the brain and spinal cord. Incidence of Hib meningitis has increased over the past 3 decades. Is this rise associated with the administration of other vaccines and consequent impairment of the immune system? 15% of cases of Hib disease present with epiglottis, a potentially dangerous condition of airway obstruction. The disease is spread by sneezing, sharing handkerchieves, or contact with the faeces of an infected child. It is more common among children attending nursery.
TB meningitis
TB meningitis is very rare, usually beginning in the lungs. See page on Tuberculosis.