Both of these bacteria are spread by the respiratory route and the incidence of disease is highest from late December to March. In the past two years notifications of meningitis, and in particular septicaemia, have increased. Doctors who suspect that a patient is suffering from meningitis or meningococcal septicaemia have, by law, to notify the patient's local authority to enable public health measures to be taken. Predominantly, notification takes place when meningococcal meningitis is suspected, but differentiating between viral and bacterial meningitis can be difficult. The recent rise in notifications may, therefore, represent better awareness.
Diagnosis is confirmed by culturing the organism.
Meningococci are classified according to their serogroup. The common serogroups are A, B, C, Y and Q135. The UK is affected by group B and C organisms. Group B strains are responsible for around 60 per cent of all cases of the disease, and group C the majority of the rest. The highest attack rates occur in children under one, after which they decline.