The Issue of Parasitism

Original text Luciano Carlos Cunha · Volume VII, p. 91 of the PDF edition · English translation

A common belief is that the proposal to help wild animals would have to prohibit treating cases of parasitism, since it would save a single animal at the cost of the deaths of many, making the resulting situation worse.

However, death is not bad intrinsically, but because of the good it could prevent from being enjoyed. Thus, for the number of deaths to be relevant in determining how bad a situation is, they must be deaths:

(1) Of sentient beings and;

(2) Of sentient beings whose prospects of future life are positive to the point of being preferable to death.

Thus, in cases where the parasites are not sentient and the host is sentient, even if treating the parasitism results in more deaths, the resulting situation is better, since death is not a harm for such parasites.

In the case of parasites that are sentient, it would have to be assessed whether their lives would be at least minimally meaningful. If they are not (and it is not possible to make them so), then death would not represent a greater harm for them than remaining alive. Thus, there could be a justification for treating the victim even if the parasites were sentient, and even if doing so means a greater number of deaths.

Suppose, for the sake of argument, that in a given case the parasites would be more harmed if they died, and that the right decision were therefore not to treat the host. Even so, there could be no objection whatsoever to preventing future cases of parasitism (for example, through sterilization), since refraining from producing new beings is not the equivalent of killing beings who already exist.

Moreover, not treating parasitism would probably result in a greater number of deaths and more suffering. As explained below, this may be so in the short term and is certainly so in the long term.

Even in the short term, not treating the host could result in a greater number of deaths. There are cases in which it is possible to remove the parasites (for example, larvae) alive. And there are cases in which removing the parasites is the only way to enable them to have a longer life. For example, in the case of larvae that will become flies, this will only happen if, at a certain point in their development, they are outside the host's body. Otherwise, they will die there.

However, suppose that treating the host always means a greater number of deaths in the short term (assuming that the parasites are sentient, which is often not the case). Almost all parasites are animals who reproduce by maximizing the number of offspring. If they are sentient, as we saw in Chapter 3, the result of this reproductive strategy is also the maximization of the number of deaths and of suffering for the members of these species themselves. Thus, given that the reproductive potential of these animals is gigantic, not treating the host will result in the parasites continuing to reproduce and to infect new victims (and therefore will result in a greater number of deaths, more suffering, a greater number of lives dominated by suffering, a greater number of extremely short lives, etc.). This gives us reasons not only to treat victims of parasitism who are already infected but, above all, to prevent parasitism in general¹⁴⁰.

Therefore, it is false that the proposal to prevent natural harms would prohibit treating cases of parasitism.