Meningococcal disease, also called meningococcal meningitis, is infections caused by the bacterium meningococcus (Neisseria meningitidis). If left untreated, the death rate is high. However, it can be prevented by vaccines. The disease is best-known for causing meningitis. It also causes blood infection, which then leads to sepsis.
There are over 2,600 cases of bacterial meningitis in the United States per year. In developing countries, there are over 333,000 cases per year. The case death rate is between ten and twenty percent.