What is meningitis, which led to Damien Martyn being put in induced coma?

Former Australia cricketer Damien Martyn has been placed in induced coma after being diagnosed with meningitis. Meningitis is a serious infection that causes inflammation of the protective membranes covering the brain and spinal cord. It is usually triggered by bacteria, viruses or fungi and can lead to high fever, severe headache, vomiting, neck stiffness, confusion and seizures.