Sentence:  It was so cold and so wretched that a sort of desperate gaiety <WSD>infected</WSD> all of them , like people stormbound or shipwrecked or caught in some other freak of circumstance so that time stood still and minor anxieties fell away and the only important thing was to cling together and survive . 
Meaning of the word marked with <WSD> tags:  contaminate with a disease or microorganism