Companion Animal Heartworm and Parasite Prevention

Internal and external parasites cause significant welfare harm in companion animals — preventive care is one of the most cost-effective welfare investments available.

Key Facts

Heartworm disease, transmitted by mosquitoes, is preventable with monthly medication but fatal if untreated
Fleas cause allergic dermatitis, tapeworm transmission, and anemia in heavy infestations
Ticks transmit Lyme disease, ehrlichiosis, and other serious diseases to both animals and humans
Year-round parasite prevention is recommended in most regions where climate supports parasite activity
Resistance to antiparasitic drugs is increasing in some parasite populations

Welfare Considerations

Parasite prevention is one of the most impactful routine welfare interventions for companion animals. Heartworm disease causes chronic cardiac and pulmonary damage before causing death — entirely preventable with monthly medication. Flea infestation causes skin inflammation, self-trauma from scratching, and secondary infections. Tick-borne diseases cause fever, joint pain, and organ damage. The welfare cost of undertreated parasitism is significant, and the cost of prevention is modest. Owners who maintain consistent, veterinary-recommended parasite prevention programs deliver substantially better welfare outcomes for their animals than those who treat reactively.

What You Can Do

Discuss year-round parasite prevention with your veterinarian for your specific region and animal
Maintain consistent monthly heartworm prevention in dogs and cats in endemic areas
Use veterinarian-recommended flea and tick prevention — not all products are equally effective or safe
Check your animals for ticks after outdoor activity in tick-endemic areas
Report any suspected treatment failures to your veterinarian promptly