External and internal parasites cause significant suffering to companion animals, and appropriate prevention requires veterinary guidance rather than blanket treatment that may harm non-target species.
Animals with flea infestations experience constant pruritic (itching) distress that severely reduces quality of life. Mange mites cause intense suffering through burrowing into skin. Intestinal worms cause weight loss, anaemia and abdominal pain. Tick-borne diseases cause severe illness. However, indiscriminate parasite treatment with broad-spectrum products causes environmental harm, particularly to dung beetles and aquatic invertebrates, creating a welfare trade-off that requires targeted approaches.