The only parasites I have found in deer, down here at least were liver flukes. I don't know if the eggs, are in the blood or not.
I would think the salt in the seasoning or marinade, would pretty much do the little critters in, as well as being dried. But I don't know if it would kill them or not. Some of them are hardy little farts. Maybe a good Bourbon marinade would pickle them. But it was what our ancestors lived on for quite some time. Of course worms were a problem at times. Whether or not from the jerky I don't know. They would supposedly just keep adding stuff to the pot as they obtained it. Not much was thrown out because it was more than a couple days old......
Don't forget they didn't have a wash your hands sign in the out house. If you wanted a biscuit, you just reached out and got it yourself.
They ate a lot of bad meat, drank bad water, bad whiskey,consorted with bad women, over worked themselves, abused their bodies, and teeth, and somehow still lived to the ripe old age of fifty!
Wayne