An acute bacterial disease caused by Neisseria meningitides that presents usually, but not always, with a rash (non blanching petechial or purpuric rash), progressively developing signs of meningitis (fever, vomiting, headache, photophobia, and neck stiffness) and later leading to confusion, delirium and drowsiness. Neck stiffness and photophobia are often absent in infants and young children who may manifest nonspecific signs such as irritability, inconsolable crying, poor feeding, and a bulging fontanel. Meningococcal meningitis may also present as part of early or late onset sepsis in neonates. The disease is potentially fatal. Surviving patients may develop neurological sequelae that include sensorineural hearing loss, seizures, spasticity, attention deficits and intellectual disability.