This bacterium can infect the bloodstream or the meninges, a thin lining covering the brain and spinal cord. When this bacteria infects the brain it is called meningitis. Meningitis can cause blood poisoning, blindness, deafness, and can damage many organs. Ten to fifteen percent of people with the illness die, often within hours of the first signs of illness.
Meningococcal disease is a relatively rare disease and is usually found as a single sporadic case.
Bacterial meningitis is spread from person to person by direct transfer of saliva. Even if the bacterium is spread from person to person, it does not mean the next person will contract the disease. Most persons develop immunity and become carriers. One in ten people carry this particular germ in the back of their nose and throat without any signs of illness. Rarely a person develops the disease instead of becoming a carrier.