Sickness is catching. Oh, were favour so,
Yours would I catch, fair Hermia, ere I go.
– William Shakespeare
A Midsummer Night’s Dream, Act 1, Scene 1. Sickness is contagious, says Helena. But she wishes that her Hermia’s beautiful eyes and musical voice were contagious too, so she could catch them. She envies how Hermia is able to attract Demetrius with her beauty.