Meningitis is an inflammation of the lining of the brain and can be caused by several types of germs, some are bacteria and some viruses.
The illness needs quick treatment with antibiotics to increase the chances of a full recovery.
Germs which cause bacterial meningitis are very common and live naturally in the back of the nose and throat.
They spread between people in droplets from the mouth and nose, but cannot survive for long outside the human body and only rarely overcome a person's immune system to cause meningitis.
Vaccines are available for some forms of meningitis. However there is not yet a vaccine for all forms of meningococcal bacteria.
These are the symptoms to look out for:
NVery young children may become drowsy, irritable and off their food. They may be distressed, feverish, have vomiting, diarrhoea or fits, neck stiffness and a rash of reddish purple spots or bruises.
NIn older children and adults the symptoms will be a headache, neck stiffness, eye discomfort from bright lights, vomiting, fever, back or joint pains, confusion and a rash may also occur.
The illness usually develops over one or two days but can also develop within hours.
For more information, contact the Meningitis Research Foundation's helpline on 0808 800 3344 or the National Meningitis Trust on 0845 6000 800.