Causes of Meningitis

Meningitis is an infection involving the covering on the brain and spinal cord, called the meninges. Common symptoms associated with meningitis include a severe headache, a high fever and a stiff neck. Viruses, bacteria and fungus may all cause a meningitis infection. Each form of the infection cause similar symptoms, but treatment options vary, depending on the cause. Some individuals may also experience chronic meningitis. Preventing meningitis ranges from proper hand washing to vaccines that help prevent contracting the bacteria that cause it.


The most common form of meningitis is from a virus. Many types of viruses may cause the infection in the meninges. The most common type of virus that causes meningitis is the family of enteroviruses. These viruses commonly circulate in the summer and fall and account for more than 90 percent of meningitis cases, according to the Mayo Clinic. Other viruses that can infect the meninges include lyme disease, herpes and West Nile. The viral form of meningitis usually runs its course and resolves itself without medical treatment.


Bacterial meningitis is the most severe form of the condition. Several types of bacteria may invade the body and travel to the brain to cause the meningitis infection. Common strains of bacteria that cause meningitis include streptococcus pnuemoniae, neisseria meningitides, listeria, Escherichia coli and Haemophilus. Vaccines are available to help decrease the possibility of becoming sick after exposure to the Haemophilus, streptococcus and neisseria bacteria. Mothers may pass the bacterial infection to infants in the birth canal, warns the Merck Manuals of Health Information. Bacterial meningitis causes more severe symptoms and possible complications–including death–than other forms of meningitis.


Fungal infections leading to an infection of the meninges are not as common as bacterial or viral infections, but they are still possible. Cryptococcal meningitis is the fungal form of the condition. The fungus, found in soil, typically infects individuals with compromised immune systems, such as individuals with AIDS or lymphoma. This rare condition affects about five out of every 1 million people in the U.S., states MedlinePlus. Antifungal medications treat this form of meningitis.

Rare Causes

Additional causes for meningitis are rare but may occur. Some slow-growing organisms may cause chronic meningitis, explains the Mayo Clinic. Other causes are from noninfectious agents and include medications, chemical irritants, tumors and drug allergies.

About this Author

Abigail Adams began her freelance writing career in 2009, teaching others about medical conditions and promoting wellness by writing on online health and fitness publications. She is educated and licensed as a registered nurse receiving her degree from North Georgia College and State University.