The highest risk group is children under the age of five, followed by adolescents of about 13-17. Children often develop a respiratory form of the disease - pneumococcus. It is also more likely in persons who are immunosuppresed. However, meningococcus also exists as part of the normal bacteria in the nose and larynx of about 10% of adults and causes no symptoms.
The bacteria was first isolated in 1887. The bacteria only affects humans as it cannot process the iron it needs from other sources.
Meningococcus travels in the saliva and is easily passed from person to person by coughing or casual mouth-to-mouth contact. The first symptom of the meningitis is usually fatigue which quickly progresses to fever and neck stiffness, and can quickly lead to coma and death. Even with aggressive treatment, about 10% of the patients at the later stages of the disease will die.
Unfortunately, several other bacteria also cause meningitis and it is not always easy to determine which organism is at fault. Multiple cases point to meningococcus, but in isolation it is often mistaken for the forms caused by influenza or streptococcus. However, meningococcus is immune to the most common antibiotics and anti-virals used to treat those conditions. Making it more difficult is that when treated with antibiotics, the bacteria may be undetectable in the blood, but may still be thriving in the cerebro-spinal fluid. As such, a lumbar puncture is recommended when the disease is even suspected as the presence of the bacteria there will provide a definitive diagnosis.
Treatment is generally with cephalosporin.
Patients who are even suspected with meningococcus are a medical emergency and should seek treatment as soon as possible. The presence of neck stiffness and a rash are the most important symptoms in a differential. In addition, anyone who has been in contact with the person should also be examined and treated.