Meningitis is an inflammation of the fluid and membranes that cover the brain and spinal cord. Every year over 1 million1-3 people worldwide are affected by meningitis. Infection is by far the most common cause of meningitis and is caused by many different germs: viruses, bacteria, fungi and parasites.
Bacterial meningitis is aggressive, develops quickly within a few hours and can lead to permanent disability or death in a matter of hours.
It is fatal in up to 10 to 20% of cases and accounts for around 170,000 deaths around the world each year1. The great majority of these deaths occur within 24-48 hours after the onset of symptoms.
There are different types of all three bacteria called serogroups or serotypes. For example, meningococcus serogroups A, B, C, W and Y are responsible for over 95% of meningococcal meningitis and septicaemia cases.
Septicaemia (blood poisoning) is a potentially life-threatening infection that occurs when the bacteria that cause meningitis get into the bloodstream. The infection may be seen alone or in addition to meningitis.
Many people carry meningitis bacteria in their nose and throat. These bacteria usually cause no harm and help to build up immunity against infection. Only on rare occasions do the bacteria invade the body and cause disease. .
The bacteria spread from person to person through respiratory droplets for example, by coughing and close contact such as kissing)
Viral meningitis is the most common kind of meningitis and is usually less severe. Most patients recover without any permanent damage, although full recovery can take many weeks or months.
Many viruses can cause meningitis, and these usually spread through respiratory droplets (kissing, coughing, sneezing) or by faecal contamination. The most common group, enteroviruses, live in the respiratory and intestinal tracts and can cause colds and sore throats usually with fever, headache, and muscles aches. From time to time, enteroviruses spread to the meninges and cause meningitis.
The mumps virus can also cause meningitis, but due to the combined measles-mumps-rubella vaccine (MMR), this form of meningitis is now rare in countries with high MMR immunisation rates.
Vaccines are not available to protect against many types of viral meningitis, but good hygiene can help prevent spread.
Fungal meningitis can be severe but occurs infrequently.
Fungal meningitis is not contagious and spreads by inhaling fungal spores from the environment. Most cases occur in people with impaired immune systems, including people with AIDS.
Vaccines are not available to protect against fungal meningitis.
It is also possible to contract meningitis from parasites or through non-infectious means like cancers, lupus, certain drugs, head injuries, brain surgery, or an existing condition of the skull or spine.