How Heartworm Spreads and Why Prevention Matters
Heartworm is spread when a mosquito bites an infected animal and then bites your pet. The larvae develop into worms that can live in the heart and lungs. Treatment for heartworm disease in dogs is complex and can be costly; there is no approved treatment for cats.
Prevention is generally safer and more affordable than treatment. Monthly preventives work by killing the immature stages of the parasite before they can develop into adult worms. Year-round prevention is recommended in many areas, including Iowa. We offer long-acting injectable options for heartworm prevention in dogs, as well as injectable flea and tick prevention for eligible patients. These options provide year-round protection without monthly dosing.
Heartworm Testing and Prevention Schedules
Dogs should be tested for heartworm before starting prevention and then annually. Testing helps ensure your pet is free of infection and that the preventive is working. Cats may be tested before starting prevention; your veterinarian will advise based on risk.
Give heartworm prevention on the same day each month. Missing doses can leave your pet vulnerable. If you miss a dose, contact your veterinarian for guidance on when to give the next dose and whether testing is recommended.
Indoor Pets and Heartworm Risk
Indoor pets can still be bitten by mosquitoes that enter the home. Heartworm has been reported in all 50 states. Many veterinarians recommend year-round prevention for both indoor and outdoor pets to reduce the risk of infection.
If you have questions about your pet's risk or which product to use, your veterinarian can help. They can recommend a preventive suited to your pet's species, size, and lifestyle.
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Frequently Asked Questions
Do cats need heartworm prevention?
Yes. Cats can get heartworm disease, and there is no approved treatment for infected cats. Prevention is the best approach. Your veterinarian can recommend a product and schedule based on your cat's risk.
Why does my dog need a heartworm test every year?
Annual testing helps ensure your dog is free of infection and that the preventive is working. If a dog becomes infected despite prevention, early detection allows for appropriate management. Testing is typically quick and can be done during a wellness visit.
What happens if I miss a dose of heartworm prevention?
Contact your veterinarian. They may recommend giving the missed dose and continuing on schedule, or they may advise testing depending on how long the gap was. Do not double up on doses without veterinary guidance.