Science & Technology in Action

11th Edition

Meningococcal disease

Health Service Executive

Meningitis is an inflammation of the meninges — three layers of tissue that surround and protect the brain and spinal cord. The classical symptoms of meningitis are fever, vomiting, drowsiness, feeling confused and irritable, stiff neck and photophobia. The final two symptoms are often absent in small children.
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Lesson excerpt

There are three main causal organisms of meningitis; viruses, bacteria and, very rarely, fungi. 

Viral meningitis, also known as “aseptic meningitis”, is the commonest type of meningitis and is most frequently seen in children. It is a milder disease than bacterial meningitis and is rarely fatal, with a mortality rate of less than 1 in 100. People with viral meningitis may have severe symptoms but they usually recover completely. There is no specific drug treatment for viral meningitis. Antibiotics are of no value in treating viral diseases as they have no effect on viruses.

Fungal meningitis is very rare. It is generally caused by yeast type fungi such as Candida albicans, the cause of thrush. It normally only occurs in people with a compromised immune system, e.g. in people who are on chemotherapy. W will therefore focus on bacterial meningitis, particularly that caused by meningococcal bacteria.

Bacterial meningitis is caused by a variety of bacteria; for example pneumococcal meningitis is caused by Streptococcus pneumoniae and Hib meningitis is cause by Haemophilus influenzae type b. However we will focus on meningococcal meningitis, as it is the most common form of bacterial meningitis, which is caused by the gram negative diplococcus Neisseria meningitidis. This is by far the most dangerous form of the disease because it can progress very quickly and cause serious harm or even death in a matter of hours. 

N meningitidis is part of the normal non-pathogenic flora of the nasal and throat regions of 5-15% of adults, but it is at its most frequent in college students where up to 25% may be carriers. Very occasionally the bacteria can find its way to other parts of the body, such as the meninges, or blood and cause an harmful infection. N. meningitidis is only found in humans because humans provide a suitable source of the iron it requires for its metabolism. It is spread by respiratory droplets, which are most efficiently generated by coughing, sneezing and mouth kissing.

True or False?

  1. Meningitis is inflammation of the membranes surrounding the central nervous system. true
  2. Viral meningitis is normally more serious than bacterial meningitis. false
  3. Meningococcal disease is only contracted by physical contact. false
  4. Only children contract meningococcal disease. false
  5. There is an effective vaccine for meningococcal B disease. true
  6. The vaccine against meningococcal C disease is very safe and effective. true
  7. The MenC vaccine protects against all other forms of the disease. false
  8. Anti-viral drugs cure meningococcal disease. false
  9. The rash associated with meningococcal disease does not disappear when a glass is held against it. true
  10. If you suspect meningococcal disease you should seek emergency medical help true