Meningococcal meningitis is a highly contagious disease of the meninges, a thin lining that surrounds the brain and spinal cord, caused by the bacterium Neisseria meningitides (meningococcus). It can be life-threatening in infants, children, and young adults. The deadly effects of meningococcal meningitis are particularly seen in sub-Saharan Africa in the "meningitis belt," extending from Senegal in the west to Ethiopia in the east with an estimated 430 million people at risk. Group A meningococcus is the main cause of meningitis epidemics, accounting for 80 to 85 percent of all cases. In 2009, there were 13,440 cases in Niger with a case fatality ratio of 4.2 percent. Meningococcal meningitis epidemics place a great burden on the overtaxed health systems of affected countries. Mortality rate exceeds 50 percent without treatment and 5-10 percent within 24-48 hours after onset, even with appropriate medical attention. Over 25 percent of survivors suffer from hearing loss, permanent brain damage or necrosis leading to limb amputation.