Meningitis

Neisseria meningitidis is a leading cause of bacterial meningitis in sub-Sarahan Africa. Photo: Public Library of Science (PLoS).

Meningitis is an infection of the lining of the brain and spinal cord, sometimes referred to as spinal meningitis. The most common causes of meningitis are viral and bacterial; fungal and parasitic infections are much less common. Knowing whether meningitis is caused by a virus or bacterium is important because the severity of the disease and its treatment may depend on the type of infection.

  • Viral meningitis is generally not life-threatening and may resolve without specific treatment.
  • Bacterial meningitis can be more serious than viral meningitis because its onset is rapid and infection is associated with a significant risk of death. Many survivors of bacterial meningitis have long-term disabilities, such as loss of limb(s), deafness, nervous system problems, or brain damage.

Before the 1990s, Haemophilus influenzae type b (Hib) was the leading cause of bacterial meningitis among children younger than 5 years old, but vaccines given to all children as part of their routine immunizations have reduced the occurrence of invasive disease due to Hib. Today, Streptococcus pneumoniae and Neisseria meningitidis (meningococcus) are the leading causes of bacterial meningitis. In fact, meningococcal bacteria are responsible for the majority of epidemics in sub-Saharan Africa.