What is Heartworm Disease in Dogs?
Heartworm disease is a severe and potentially fatal condition in dogs caused by the parasite Dirofilaria immitis. This disease also affects cats, ferrets, and other mammals. Heartworms are large worms that can grow up to 12 inches long and live in infected animal's hearts and pulmonary arteries. The worms take about six to seven months to mature and can survive in the heart for several years.
As heartworms increase in number, they block normal blood circulation, putting strain on the heart and potentially causing heart failure along with other serious health issues. If not treated promptly, heartworm disease can become fatal.
Symptoms of Heartworm Disease in Dogs
The severity of heartworm disease varies based on the number of worms present and the dog's overall health. Common symptoms include:
- Persistent cough
- Lethargy and fatigue
- Reduced ability to exercise
- Difficulty breathing
- Weight loss
- Swollen abdomen (ascites) due to fluid buildup
- Collapse or sudden death in severe cases
Early detection is crucial to preventing complications, making regular veterinary check-ups essential.
Causes and Transmission of Heartworms in Dogs
Heartworm disease is transmitted via mosquito bites. When a mosquito bites on an infected dog, it ingests tiny larvae called microfilariae present in the dog's blood. These larvae mature into an infectious stage within the mosquito. Upon biting another dog, the mosquito transfers the larvae, which then enter the new host's bloodstream, develop into adult heartworms, and begin reproducing, perpetuating the cycle.
Heartworms have a lifespan of 5 to 7 years in dogs, with males growing up to 6 inches and females up to 12 inches. Prevention is essential, as once infected, treatment is complex and costly.
Diagnosis of Heartworm Disease
Veterinarians use two primary tests to diagnose heartworm disease:
- Antigen Test: Detects proteins released by adult female heartworms.
- Microfilariae Test: Identifies the presence of baby heartworms in the bloodstream.
Testing Guidelines:
- Puppies under 7 months: Can start prevention without testing but should be tested at 6 months, then again 6 months later, and annually thereafter.
- Dogs over 7 months: Should be tested before starting prevention, then retested in 6 months and annually.
- Dogs with missed doses: Should be tested immediately, then retested after 6 months and annually.
Regular heartworm testing is crucial to ensure early detection and treatment, even for dogs on preventive medication.
Prevention of Heartworm Disease
Preventing heartworm disease is easier and safer than treating it. Monthly and long-term preventive medications are highly effective in keeping dogs safe. Options include:
-
Oral Preventatives:
- Ivermectin (Heartgard Plus, Tri-Heart)
- Milbemycin (Interceptor, Sentinel)
- Topical Preventatives:
-
Injectable Preventatives:
- Moxidectin (ProHeart 6, ProHeart 12) – provides protection for 6 to 12 months
Using mosquito-repelling products like Advantix can add an extra layer of protection. Year-round prevention is recommended, as mosquitoes can survive in various climates.
Treatment and Recovery from Heartworm Disease
If a dog is diagnosed with heartworms, treatment involves multiple steps:
- Restricting Physical Activity: Exercise increases the risk of complications.
- Medication to Kill Worms: A series of injections are administered to eliminate adult heartworms.
- Monitoring for Side Effects: Treatment can cause inflammation and complications, requiring close veterinary supervision.
- Follow-up Testing: After treatment, additional tests confirm the elimination of heartworms.
Since treatment is costly and carries risks, prevention is always the best approach to protecting your dog's health.
Final Thoughts
Heartworm disease poses a serious risk to dogs but is entirely preventable. By maintaining consistent, year-round preventive care and scheduling routine check-ups, you can help keep your dog healthy and protected from heartworm infections.
Protect your pet today by choosing the right heartworm prevention plan recommended by your veterinarian.
