Let's start here: I take issue with the idea of intentionally infecting anyone with anything. The connotation of the word "infect" is inherently negative, and more importantly, it suggests a lack of agency on the part of the infected individual.
Let's not suggest that students don't already have a passion for learning. At worst, they don't have a passion for learning THAT or THIS.
And that's cool, honestly. I don't have a passion for learning forensic science (gross) or linear algebra. All I can do is to be excited myself and allow students the space to put their own spin on what we're learning.
So let's do that. Let's create assignments with thousands of possible iterations, and give students the platform to try things out and see what works for them. Let's not make it complicated. We can remind them that they love learning, and let reawakening serve as our guiding metaphor instead of infection.