Bacterial meningitis

Meningitis is acute or chronic inflammation of the protective membranes covering the brain and spinal cord, collectively called the meninges ^[1]. The inflammation may be caused by infection with viruses, bacteria, fungi, or parasites, or by non-infectious causes such as malignancy, subarachnoid hemorrhage, chronic inflammatory disease, or certain drugs ^[1].

The most common symptoms are fever, intense headache, vomiting, neck stiffness, and occasionally photophobia ^[1]. Other symptoms include confusion or altered consciousness, nausea, inability to tolerate loud noises, and a non-blanching rash may be present ^[1]. Young children often exhibit only nonspecific symptoms such as irritability, drowsiness, or poor feeding ^[1].

Since the 1980s, many countries have included immunization against Haemophilus influenzae type B in their routine childhood vaccination schemes, practically eliminating this pathogen as a cause of meningitis in young children in those countries, though in countries with the highest disease burden the vaccine remains too expensive ^[1]. Immunization against mumps has led to a sharp fall in mumps meningitis, which before vaccination occurred in 15% of all mumps cases ^[1]. Meningococcus vaccines exist against groups A, B, C, W135 and Y, and in countries where the group C vaccine was introduced, cases decreased ^[1].

Most bacteria causing meningitis are carried in the human nose and throat and spread from person to person by respiratory droplets or throat secretions ^[2]. Group B streptococcus is often carried in the gut or vagina and can spread from mother to child around the time of birth ^[2].

Some forms of meningitis are preventable by immunization with meningococcal, mumps, pneumococcal, and Hib vaccines ^[1]. Giving antibiotics to people with significant exposure to certain types of meningitis may also be useful for preventing transmission ^[1].

1. 1 Wikipedia contributors. Meningitis - Wikipedia [Internet]. Wikipedia. cited 3 Sept 2026. Available from: https://en.wikipedia.org/wiki/Meningitis
2. 2 World Health Organization. Meningitis [Internet]. cited 23 Oct 2026. Available from: https://www.who.int/health-topics/meningitis
3. 3 GlobalID Disease Ontology. GlobalID ontology concept D235: Meningitis (all reported etiologies) [Internet]. cited 23 Oct 2026. Available from: https://github.com/xmusphlkg/globalID2/blob/development/configs/disease_ontology.json