What's up with the parasite affecting campaign?

I have not finished the game, I've gotten just past the habitation yellow part after the grabby hands monster.

But I did do a parasite run and completed it. Since completing the parasite I've noticed a few Parasite mode objects appearing in the campaign, mainly the Wrench and the Locator. Also sometimes I notice my screen goes green and my character coughs like they've been hit by the enemies in that game.

This seems intentional by the, but does it ever get explained? I'm very curious, are we the same character from the parasite in some way? Maybe the dead body with the wrench and the Locator you find at the start?