Why Did God Make Germs?

My five year old has put forth an avalanche of questions in the past year. 

"What does Superman's cape do?" (it looks cool)
"Why do you and Daddy have to be alone sometimes?" (we like each other)
"Why do some animals eat plants and others eat meat?" (they eat what their teeth and stomachs can handle)
"Are you a safe driver?" (of course, but no one else on the road is)
"What's 10 minus 12?"  (-2  - he's fascinated by the notion that zero is not the smallest number)
"What's the biggest number?" (infinity - this thrills him, too)

And most recently, "why did God make germs?" 

I pondered my response, knowing the best answer probably wasn't "so that Mommy could see just how little sleep she could have without cracking up!" or "so that we could see just how many viruses the entire family could catch in the first month you are back at school!"

I paused, then replied, "no one really knows why God does things but I it seems to me that if we didn't get sick we might not appreciate it when we feel well.  Feeling well is a pretty terrific thing, don't you think?"  He did. 

He turned to the toddler and said, "you don't want to get sick do you?" Eyes wide, the toddler shook his head.  "So don't put your finger in your nose!"

That's my boy!