What causes the measles?

Measles was once a common childhood infection caused by virus of the paramyxovirus group. It is characterised by spots and a respiratory infection causing high fever, cough and runny nose. It is very contagious - nine out of 10 children exposed to the virus will develop measles.

Babies generally have a natural immunity to measles for the first six to eight months of their life, due to immunity passed on from their mother.