All 3 Uses

measles
in
The Railway Children
(Edited)

Mother began to be afraid that he might be sickening for measles, when suddenly he sat up in bed and said: 'I hate gruel — I hate barley water — I hate bread and milk.'
p. 3.6

measles = a highly contagious viral disease marked by distinct red spots followed by a rash
Crying is catching, I believe, like measles and whooping-cough.
p. 64.9 *

measles = a highly contagious viral disease marked by distinct red spots followed by a rash; occurs primarily in children and was very common before vaccinations were widely given to prevent it
Which is quite true, if you come to think of it, and a useful thing to remember in seasons of trouble — such as measles, arithmetic, impositions, and those times when you are in disgrace, and feel as though no one would ever love you again, and you could never — never again — love anybody.
p. 226.9

measles = a highly contagious viral disease marked by distinct red spots followed by a rash

Definitions:

(1) (measles)
a highly contagious viral disease marked by distinct red spots followed by a rash; occurs primarily in children
(2) (meaning too rare to warrant focus)