The idea being debated
Parasitism happens when one living thing lives inside or on another, feeding on it and harming it. Many people think it would be wrong to help an animal with parasites, because it would save one animal at the cost of the deaths of many parasites.
Death is only bad for some
Remember: death isn't bad in itself. It's bad because it takes away the good things someone would still have lived. So death is only bad:
- for beings that can feel;
- and whose future life would be good enough to be worth more than dying.
Parasites that can't feel
Many parasites, like very simple worms, bacteria, and fungi, probably can't feel anything. In these cases, treating the host animal, who can feel, makes the situation better, even if lots of parasites die, because death isn't bad for them.
Parasites that can feel
If the parasites are sentient, we'd need to think about whether their lives would be at least somewhat good. And even if, in some case, the right decision were not to treat, the author points out that not treating usually leads to more suffering and more deaths overall, because parasites multiply and attack other animals.
In short
- Death is only bad for those who can feel and would have a good life ahead.
- Many parasites probably can't feel.
- So treating the host usually makes things better.