Meningitis is most often caused by either a virus or one of several types of bacteria:
- Bacterial forms of meningitis can be extremely dangerous and fast-moving and have the greatest potential for being fatal. The long-term effects of bacterial meningitis can include multiple amputations, hearing loss and kidney damage. Many (but not all) forms of bacterial meningitis can be prevented by vaccination.
- Viral meningitis has similar symptoms to bacterial meningitis, but for the most part is neither as deadly nor as debilitating. There is no specific treatment available for viral meningitis, but most patients fully recover over time.
Although meningitis is usually caused by bacteria or viruses, it can also be caused by injury, cancer, certain drugs or other microorganisms like fungi and parasites. Please visit CDC’s meningitis page for more information.
Major Bacterial Types of Meningitis
The three main types of bacterial meningitis in the U.S. are:
Meningococcal disease (Neisseria meningitidis)
Meningococcal disease is expressed primarily as either meningitis, an inflammation of the membranes surrounding the brain and spinal cord, or meningococcemia, the presence of bacteria in the blood. Meningococcal disease is the most common type of bacterial meningitis today in U.S. children age 2-18.
The bacteria that cause meningococcal disease reside in the throats and nasal passages of approximately 10 percent of the general population. Researchers are unsure why the bacteria cause some people to become sick while most of the population is not affected.
The families who founded and work with NMA were affected by meningococcal disease. Education about the disease and its prevention is the focus of our educational efforts.
Pneumococcal disease (Streptococcus pneumoniae)
Like meningococcal disease, pneumococcal disease can cause both meningitis and blood infection and it can be serious or fatal. Pneumococcal bacteria can also cause otitis media and other infections. Young children, older adults and those with certain health conditions are at greatest risk for pneumococcal disease. The U.S. immunization schedule for children includes a series of vaccines to help protect them from pneumococcal infection. Some older children and adults are also recommended for pneumococcal vaccination.
Hib (Haemophilus influenzae type b) disease
Hib disease primarily attacks the very young, but has been nearly eradicated in the U.S. since the introduction of infant vaccination programs against Hib in the 1980s. Before the use of vaccination, Hib was the top cause of meningitis in children under the age of five in the U.S.