Meningitis is the inflammation of the protective membranes covering the central nervous system, known collectively as the meninges. Meningitis may develop in response to a number of causes, most prominently bacteria, viruses and other infectious agents, but also physical injury, cancer, or certain drugs. While some forms of meningitis are mild and resolve on their own, meningitis is a potentially serious condition owing to the proximity of the inflammation to the brain and spinal cord. The potential for serious neurological damage or even death necessitates prompt medical attention and evaluation. Infectious meningitis, the most common form, is typically treated with antibiotics and requires close observation. Some forms of meningitis (such as those associated with meningococcus, mumps virus or pneumococcus infections) may be prevented with immunization.