Public Health England say:
‘Around 10% of the population carries the meningococcus in the back of their throat or nose without causing any illness. It is transmitted from person to person by inhaling respiratory secretions from the mouth and throat or by direct contact (kissing). Close and prolonged contact is usually needed for transmission.
Occasionally, the meningococcus can cause invasive disease, including meningitis (inflammation of the meninges), septicaemia (blood poisoning) and pneumonia. Young children and teenagers are at highest risk of meningococcal disease. It is not known why some individuals carry the bacteria without them causing harm while others go on to develop invasive disease.’
https://www.gov.uk/government/collections/meningococcal-disease-guidance-data-and-analysis
Meningitis was first discovered in 1805. It is treated by the prompt application of antibiotics.
http://www.uptodate.com/contents/epidemiology-of-bacterial-meningitis-in-adults
Certain types of meningitis can be induced by anti-inflammatory painkillers.
https://www.ncbi.nlm.nih.gov/pubmed/20105400Ō