Meningococcal meningitis is the most common variety of bacterial meningitis. It is high contagious and aggressive. Around five percent of people are carriers. Few develop the illness, but it is fatal in one in 10 cases. Flu-like symptoms are rapidly followed by fever, acute headaches, neck ache, stiffness and vomiting. As the bacteria attack the brain's membranes around four days later, irritability, confusion, drowsiness, convulsions or coma may occur. Treatment is by antibiotics. Vaccines are available but work only against certain varieties of meningitis. Parents are advised to have children vaccinated before they are six months old.
Meningococcol meningites are caused by a variety of serogroups of the N. meningitidis bacteria. Serogroup A is the major cause of epidemics, although serogroups B and C have caused epidemics, as well. In the United States, outbreaks currently occur as isolated cases or in small clusters of cases caused mainly by serogroup B or C. In certain developing countries, large epidemics caused by serogroup A occur frequently.
The way infective bacteria enter the body is through the upper respiratory tract. People can acquire the disease by inhaling the bacteria, by direct mouth-to-mouth contact with an infected person, or by indirect contact (for example, by touching one's nose after touching an object or a hand that was recently contaminated with an infected person's nasal secretions).
Meningococcal infections occur worldwide and at any season, although most cases appear in late winter and spring. It is primarily a disease of youth and especially of children under 10 years, though all ages may be affected. From 1939 to 1972, nearly a million people were affected by meningitis and over 150,000 died in the African countries that are wholly or partly located in that area of the Sahel and the savannah known as the 'meningitis belt' (where the rainfall is more than 300 mm and less than 1,100 mm per year). During 1982-1983 there were again serious outbreaks of cerebrospinal meningitis affecting a number of countries in both the tropical and the temperate zones. In 1989, an estimated 10,000 people died of a particularly virulent strain of meningitis in Ethiopia. In the UK in 1993 it was estimated that some 3,000 people became infected with the disease each year, and some 150 died of it.