Meningitis is an inflammation (swelling) of the lining covering the brain and/or spinal cord, which can lead to a stiff neck, headache, fever and drowsiness, or, more seriously, coma or death. Meningitis is not a disease in and of itself, but rather a symptom or complication of a disease that results from certain viral or bacterial infections.
Bacterial infections such as meningococcus, pneumococcus, Haemophilus influenzae type b and listeria can cause meningitis. Some viruses such as mumps, measles, chickenpox, West Nile virus, and some viruses related to polio, called non-polio enterovirus, can also cause meningitis. As a general rule meningitis caused by a virus is less severe than that caused by bacteria; however, anyone with symptoms should see a doctor immediately because the bacterial form can quickly progress to death.