A recent study by the Institute of Biological Sciences at UP Los Baños indicates that parasitized tilapia may be safer to eat than those not parasitized.
The parasites, Acanthocephala, are worms that accumulate heavy metal concentration in their host’s gills and intestines.
Dr. Vachel Gay V. Paller, NRCP biologist/researcher, says that the more parasites there are, the smaller the tilapia becomes. But being parasitized may be an advantage to the consumer. The parasites may save the consumers from possible heavy metal intake. After all, the parasites stay in the gills and intestines of the tilapia which consumers most likely discard.
So there you are, here is an instance where parasites are beneficial.