Meningitis is a disease that is caused by an infection or inflammation of the covering of the brain and spinal cord. Most people with meningitis have a fever, severe headache and often a stiff neck. It is impossible to tell by symptoms alone if the meningitis is caused by a virus, a bacterium, or more rarely a fungus or parasite. Viral meningitis is usually mild while bacterial meningitis is more severe and may need urgent treatment for the patient. One type of bacterial meningitis is known as meningococcal disease and is caused by the bacterium Neisseria meningitidis. This bacterial disease requires treatment for the patient as well as medications for those in close contact with the patient.
Viruses are the most common cause of meningitis. Most viral meningitis cases are mild and patients recover fully. A large number of viruses can cause viral meningitis but most are caused by common viruses known as enteroviruses. Most people who come into contact with enteroviruses do not become ill or have only mild symptoms and only a few develop meningitis. The number of cases reported varies widely from year to year and in different locations.
Meningococcal disease – infection caused by the bacteria Neisseria meningitidis – usually causes meningitis or meningococcemia (blood stream infection) which can develop very rapidly. It is considered a very serious public health emergency and is fatal in about one in 10 patients. Prophylaxis is recommended for close contacts.