Religion

I have a hard time believing it.

It mentions 50-60 million deaths during the 1500s and 1600s. During that period, European immigration was just starting in what's now the US, and most settlements were up and down the East Coast. There was some on the West Coast too, but everything in between wasn't even explored until later.

Central America, sure, maybe. It's a lot smaller. Even going up into Mexico, sure. But South America? Again, most of the settlements during that period were on the coast or close to it.

Now, if the article had said the 1700s to 1800s, I might be more inclined to believe it, even if the numbers seem very high.