Meningococcal bacteria are passed from person to person, in the secretions from the back of the nose and throat.
Person-to-person spread of meningococcal bacteria is not easy and generally requires close and/or prolonged contact with a person carrying the bacteria, who is usually completely well.
Close or prolonged contact includes living in the same household as someone or intimate (deep mouth) kissing.
The disease is not easily spread by sharing drinks, food, or cigarettes (or other smoking devices) because the bacteria do not survive well outside of the human body.
Between 5 and 25 per cent of people will have the meningococcal bacteria living in the back of their throat at some point in their lives, without showing any symptoms, and can spread it to other people. This is called carriage.
Carriage is more common among adolescents and young adults.
Diagnosis is based on the patient's history and examination. This is sometimes difficult in the early stages of the disease.
Meningococcal disease is confirmed when the meningococcal bacteria are found in a person’s blood stream (septicaemia) or the fluid that surrounds the brain and spinal cord (meningitis).
A person could have meningitis or septicaemia without having meningococcal disease – as these can also be caused by other germs.
Patients with meningococcal disease need urgent treatment with antibiotics, in hospital. Treatment will usually begin before the diagnosis is confirmed by tests.