How does death by flies work?

I've tested that out and my conclusion is that it is a random death (a rare one).

I filled my lot with trash cans and had a couple dumster woohoo to generate trash piles. With Reduce and recycle trait the trash cans filled up. I had my sim interact with the flies that appeared on it, but even with the angry moodlet she survived. I tried it many times until I switched sims. Even he survived. Then I switched back to the original sim and had her interact with flies. Suddenly, she died.

There wasn't any death notification, but the death music reminded me of "Flight of the Bumblebee".