Meningococcal disease: public health burden and control.

Meningococcal disease which is increasing globally is still associated with a high mortality and persistent neurological defects, particularly among infants and young children. Sporadic meningococcal meningitis occurs throughout the world, with seasonal variations, and accounts for 10-40% of endemic bacterial meningitis. Epidemic meningitis occurs in any part of the world but the largest and most frequently recurring epidemics have been in the semi-arid area of sub-Saharan Africa where the current pandemic is associated with attack rates exceeding 500 per 100,000 population and thousands of deaths. In the Americas and Europe serogroup B is the predominant agent causing systemic disease, followed in frequency by serogroup C. Serogroup A meningococcus was historically the main cause of epidemic meningococcal disease globally and still predominates in Africa and Asia. A range of internal and external factors predispose for epidemics such as strain virulence, carriers, humoral immunity, co-infections, low humidity and drought, population movements and crowding. To respond to the current situation and the expected spread of the disease, WHO, in collaboration with its Member States and various governmental and non-governmental agencies, has developed a sustainable plan of action for preparedness and control of meningitis.