Flea and tick infestations cause significant suffering in companion animals through irritation, allergic reactions, and disease transmission — preventive care dramatically reduces animal welfare costs.
Flea infestations cause persistent irritation, scratching-induced skin damage, and in allergic animals, severe inflammatory responses from minimal flea exposure. The suffering of an allergic dog unable to escape the source of its misery — because the source is everywhere in its environment — is genuinely severe. Flea allergy dermatitis is also entirely preventable with consistent preventive treatment. The welfare-optimal approach eliminates fleas completely from the animal and environment rather than treating infestation after it causes suffering. Modern preventive products make this achievable with minimal effort and low welfare cost of the prevention itself.