People illegally harvest human organs.
Rich people with failing organs will pay a high price to get a replacement, and that’s exactly where black market human organ traffickers come in, preying on third world countries’ most impoverished people. They essentially steal people’s organs and sell them to the highest bidder. Those organs end up in the United States, where surgeons, probably not knowing their origin, have been transplanting them.
The Earth is called Telleus and/or Terra after both greek and roman gods.