Meningococcal Meningitis

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Meningitis is defined as an inflammation of the meninges, or the membranes surrounding the brain. It is typically caused by a bacterial or viral pathogen. The bacterium Neisseria meningitidis (a Gram negative diplococcus), commonly referred to as meningococcus, is a common and dangerous cause of meningitis in humans. Numerous strains, or serogroups, of meningococcus have been identified, defined by the different sugar structures of their capsules. Outbreaks of meningococcal meningitis in most of the world are found among groups living in close quarters such as college students in dormitories, army recruits, and pilgrims. In sub-Saharan Africa, the so-called “meningitis belt” experiences thousands of fatalities from meningococcal meningitis each year, with larger epidemics every 5-12 years. However, the organism is more commonly found colonizing the nasopharynx in asymptomatic human carriers.

Meningitis has also been reported in chimpanzees, gorillas, and orangutans; however no documented case thus far involves Neisseria species. Chimpanzees have reported to be infected with Streptococcus pneumoniae and Klebsiella pneumoniae, there is a report of a single traumatic case causing meningitis from Proteus mirabilis in gorilla, and an amoeba caused meningitis in an orangutan. Notably, however, meningococcal infection has been documented as infecting chimpanzee urethra, indicating that the species is capable of infecting other great apes. This particular case did not match the known human meningococcal types.

The record to date makes clear that meningococcal meningitis is relatively frequent in humans, but rare if not absent in other nonhuman hominids. Differences in human social structure may enable transmission of infection between individuals. There may also be differences in human molecular biology that allow the pathogen to access the central nervous system. In support of the latter idea, it is interesting to note that the related species Neisseria gonorrheae, causing the sexually transmitted and uniquely human infection gonorrhea, has been demonstrated to bind to certain human proteins that inhibit the immune response. Specifically, these are human complement C4b-binding protein (C4bp) and complement factor H (fH), which inhibit the complement cascade of the immune system. No similar investigation of Neisseria meningitidis has been published. Further, several strains of meningococcus contain the sugar sialic acid in their capsule; human genes related to this molecule are highly enriched for unique changes. These or other candidate molecules may underlie the species specificity of meningitis caused by Neisseria meningitidis.


Timing of appearance of the difference in the Hominin Lineage as a defined date or a lineage separation event. The point in time associated with lineage separation events may change in the future as the scientific community agrees upon better time estimates. Lineage separation events are defined in 2017 as:

  • the Last Common Ancestor (LCA) of humans and old world monkeys was 25,000 - 30,000 thousand (25 - 30 million) years ago
  • the Last Common Ancestor (LCA) of humans and chimpanzees was 6,000 - 8,000 thousand (6 - 8 million) years ago
  • the emergence of the genus Homo was 2,000 thousand (2 million) years ago
  • the Last Common Ancestor (LCA) of humans and neanderthals was 500 thousand years ago
  • the common ancestor of modern humans was 100 - 300 thousand years ago

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  1. Neisseria meningitdis , Pollard, A. J., and Finn A. , Principles and Practice of Pediatric Infectious Diseases , (2009)
  2. Meningitis epidemics in Africa: a brief overview., Teyssou, R., and E. Le Rouzic Muros- , Vaccine, 09/2007, Volume 25 Suppl 1, p.A3-7, (2007)
  3. Human C4b-binding protein selectively interacts with Neisseria gonorrhoeae and results in species-specific infection., Ngampasutadol, J., Ram S., Blom A. M., Jarva H., Jerse A. E., Lien E., Goguen J., Gulati S., and Rice P. A. , Proc Natl Acad Sci U S A, 11/2005, Volume 102, Issue 47, p.17142-7, (2005)
  4. Amoebic meningoencephalitis caused by Balamuthia mandrillaris in an orangutan., Canfield, P J., Vogelnest L, Cunningham M I., and Visvesvara G S. , Aust Vet J, 02/1997, Volume 75, Issue 2, p.97-100, (1997)
  5. Clinicopathologic study of six cases of meningitis and meningoencephalitis in chimpanzees (Pan troglodytes)., Solleveld, H A., van Zwieten M J., Heidt P J., and van Eerd P M. , Lab Anim Sci, 02/1984, Volume 34, Issue 1, p.86-90, (1984)
  6. Meningoencephalitis secondary to otitis in a gorilla., Iverson, W O., and Popp J A. , J Am Vet Med Assoc, 11/1978, Volume 173, Issue 9, p.1134-6, (1978)
  7. Chimpanzee urethral meningococci., Brown, W J., Kraus S J., and Arko R J. , Br J Vener Dis, 1973 Feb, Volume 49, Issue 1, p.88, (1973)