Meningitis C bacteria. Coloured transmission electron micrograph (TEM) of Neisseria meningitidis serogroup C bacteria (yellow) trapped in vitrified water (blue). This bacterium is typically found in pairs (diplococcus). Neisseria meningitidis is an obligate human parasite that causes meningococcal meningitis, the inflammation of connective tissue membranes lining the brain and spinal cord. Symptoms include headache, fever, stiff neck, vomiting and delirium. It can be fatal. Treatment is with antibiotics.