Measles is an infectious disease caused by a virus of the paramyxovirus group. It infects only man and the infection results in life-long immunity to the disease. It is one of several exanthematous (rash-producing) diseases of childhood, the others being rubella (German measles), chickenpox, and the now rare scarlet fever. The disease is particularly common in both pre-school and young school children.

The measles virus mainly infects mucous membranes of the respiratory tract and the skin. The symptoms include high fever, headache, hacking cough, conjunctivitis, and a rash that usually begins inside the mouth on the buccal mucosa as white spots, (called Koplik's spots) and progresses to a red rash that spreads to face, neck, trunk and extremities. The incubation period varies but is usually 10 to 12 days until symptoms appear. Four to five days before the onset of the rash, the child has fever or malaise and then...