Meningitis is inflammation of the protective membranes covering the brain and spinal cord. The inflammation may be caused by infection and less commonly by certain drugs. The most common symptoms are headache and neck stiffness associated with fever, confusion or altered consciousness, vomiting, and an inability to tolerate light or loud noises.

It is spread by person-to-person contact through respiratory droplets of infected people. There are 3 main clinical forms of the disease: the meningeal syndrome, the septic form and pneumonia. The onset of symptoms is sudden and death can follow within hours. In as many as 10-15% of survivors, there are persistent neurological defects, including hearing loss, speech disorders, loss of limbs, mental retardation and paralysis.