Meningitis is an inflammation (swelling) of the protective membranes covering the brain and spinal cord. A bacterial or viral infection of the fluid surrounding the brain and spinal cord usually causes the swelling. However, injuries, cancer, certain drugs, and other types of infections also can cause meningitis. It is important to know the specific cause of meningitis because the treatment differs depending on the cause.
Meningitis caused by bacteria can be deadly and requires immediate medical attention. Vaccines are available to help protect against some kinds of bacterial meningitis.
Meningitis caused by viruses is serious but often is less severe than bacterial meningitis. People with normal immune systems who get viral meningitis usually get better on their own. There are vaccines to prevent some kinds of viral meningitis.
Meningitis caused by fungi is rare, but people can get it by inhaling fungal spores from the environment. People with certain medical conditions, like diabetes, cancer, or HIV, are at higher risk of fungal meningitis.
Various parasites can cause meningitis or can affect the brain or nervous system in other ways. Overall, parasitic meningitis is much less common than viral and bacterial meningitis.
Primary amebic meningoencephalitis (PAM) is a rare and devastating infection of the brain caused by Naegleria fowleri. Naegleria fowleri is a free-living microscopic ameba that lives in warm water and soil.
Sometimes cancers, systemic lupus erythematosus (lupus), certain drugs, head injury, and brain surgery can cause meningitis.
Generally, the germs that cause bacterial meningitis spread from one person to another. Certain germs can spread through food. How people spread the germs often depends on the type of bacteria. Read about common examples of how people spread the different types of bacteria to each other.
People can spread the viruses that cause viral meningitis to other people. If you have close contact with someone who has viral meningitis, they may spread the virus to you. However, you are not likely to develop meningitis. That’s because most people infected with these viruses will not develop meningitis.
Having meningitis doesn’t always mean you have meningococcal disease. And having meningococcal disease doesn’t necessarily mean you have meningitis. Meningococcal disease is any illness caused by a type of bacteria called Neisseria meningitidis. These illnesses are serious and include meningitis and bloodstream infections (septicemia). More about meningococcal disease…
Get clinical disease information, as well as vaccine recommendations and vaccination resources, for common causes of meningitis.