Feng Yi was genuinely worried that he might have contracted parasites in the swamp.
Wild snakes indeed harbor various parasites, both internal and external, and although Feng Yi did not consider himself a snake, he could take the creatures as a reference.
Before capturing the python, Feng Yi would return to the residential area hotel every day. Only during the last few days did he spend the night in the swamp. As for food, that wasn't a problem, and he made sure to maintain hygiene when he returned each day.
He didn't consume any raw food, and he was careful with drinking water in the swamp, using only bottled water he brought or water that had been filtered and boiled. They went into the swamp to catch snakes, not to shoot wilderness survival documentaries, so their material preparation was relatively thorough. If necessary, they could contact related personnel for resupply, though it would require an additional fee.