She has 'infected' everyone 'with' her enthusiasm. [=her enthusiasm has made other people feel enthusiastic too]
All the computers in the office were 'infected' by/with the same virus.
The virus has 'infected' many computers.
(..) And I'm not gonna let that happen to him. - Now, don't you do that, Sean. - What, Gerry? Don't you do that. Don't infect him with the idea that it's okay to quit. That it's okay to be a failure, because it's not okay, Sean. And if you're angry at me for being, being (..)1997 Good Will Hunting