It’s showing how the transmitting of a disease can and does commonly happen.
You have a contaminated forest so tear it down, a bat still eats the fruit and while inside of a pork plant he drops a piece on the floor and a pig just happens to eat the contaminated food.

And since there’s apparently poor regulations the pig is sold of nd eventually is being prepared for a meal by a chef who doesn’t wash his before shaking the hands of some people from another who will now travel back home give the gift that keeps on giving.