Managing external parasites like ticks, mites, and fleas involves balancing the welfare of parasitized animals against the moral consideration of parasites themselves.
Tick-borne diseases cause significant suffering in wildlife, domestic animals, and humans. Mange causes one of the most severe welfare impacts visible in urban wildlife populations: progressive hair loss, intensely itchy skin, secondary infections, and gradual debilitation leading to death. Treatment is possible but logistically challenging in wild animals. The welfare of the parasites themselves — animals with nervous systems and behavioral responses — is a genuine philosophical question with limited practical consensus.