Rates in the African meningitis belt were as high as 1 in 1,000 to 1 in 100 before introduction of a vaccine in 2010. The incidence of meningococcal disease is highest among infants (children younger than 1-year-old) whose immune system is relatively immature. In industrialized countries there is a second peak of incidence in young adults, who are congregating closely, living in dormitories or smoking. Vaccine development is ongoing.It is spread through saliva and other respiratory secretions during coughing, sneezing, kissing, and chewing on toys. Inhalation of respiratory droplets from a carrier which may be someone who is themselves in the early stages of disease can transmit the bacteria. Close contact with a carrier is the predominant risk factor. Other risk factors include a weakened general or local immune response, such as a recent upper respiratory infection, smoking, and complement deficiency. The incubation period is short, from 2 to 10 days. In susceptible individuals, N. meningitidis may invade the bloodstream and cause a systemic infection, sepsis, disseminated intravascular coagulation, breakdown of circulation, and septic shock. History
In 1884 Ettore Marchiafava and Angelo Celli first observed the bacterium inside cells in the cerebral spinal fluid (CSF). In 1887 Anton Weichselbaum isolated the bacterium from the CSF of patients with bacterial meningitis. He named the bacterium Diplococcus intracellularis meningitidis. Biotechnology
Components from Neisseria meningitidis are being harnessed in biotechnology. Its Cas9 enzyme is a useful tool in CRISPR gene editing because the enzyme is small and has distinct targeting features to the commonly used enzyme from Streptococcus pyogenes.
A comparison with MC58 showed that four genes are uniquely present in H44/76 and nine genes are only present in MC58. Of all ORFs in H44/76, 2,317 (93%) show more than 99% sequence identity.The complete genome sequence of strain NMA510612 (serogroup A) consists of one circular chromosome with a size of 2,188,020 bp, and the average GC content is 51.5%. The chromosome is predicted to possess 4 rRNA operons, 163 insertion elements (IS), 59 tRNAs, and 2,462 ORFs.There is a public database available for N. meningitidis core genome multilocus sequence typing (cMILST). Available at: https://pubmlst.org/bigsdb?db=pubmlst_neisseria_seqdef

Genetic transformation
Genetic transformation is the process by which a recipient bacterial cell takes up DNA from a neighboring cell and integrates this DNA into the recipients genome by recombination. In N. meningitidis, DNA transformation requires the presence of short DNA sequences (9–10 mers residing in coding regions) of the donor DNA. These sequences are called DNA uptake sequences (DUSs). Specific recognition of these sequences is mediated by a type IV pilin. In N. meningitidis DUSs occur at a significantly higher density in genes involved in DNA repair and recombination (as well as in restriction-modification and replication) than in other annotated gene groups. The over-representation of DUS in DNA repair and recombination genes may reflect the benefit of maintaining the integrity of the DNA repair and recombination machinery by preferentially taking up genome maintenance genes, that could replace their damaged counterparts in the recipient cell.N. meningititis colonizes the nasopharyngeal mucosa, which is rich in macrophages.