How to Get Rid of Heartworms in Dogs

Heartworm disease, caused by the parasitic worm Dirofilaria immitis, is a severe and potentially fatal condition in dogs. It’s spread through mosquito bites, leading to complications in the heart, lungs, and blood vessels. Let’s delve deep into understanding the effective ways to treat and eliminate heartworms in dogs.

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FAQs: Heartworms in Dogs

Understanding the Heartworm Lifecycle

To combat heartworms effectively, it’s essential to understand their lifecycle. After a mosquito bite, heartworm larvae enter a dog’s bloodstream, maturing into adults within 6 months. These adult worms can grow up to 12 inches long, residing in the heart, lungs, and associated blood vessels. They reproduce, further exacerbating the problem.

The Conventional Approach: Melarsomine Injections

Why Melarsomine? Melarsomine dihydrochloride is the FDA-approved treatment for adult heartworms. It’s an arsenic-based compound given via deep intramuscular injections.

Treatment Process:

  1. Doxycycline Administration: The American Heartworm Society recommends administering doxycycline for 28 days before melarsomine treatment. This antibiotic weakens the heartworms, making them more susceptible to the adulticide.
  2. Melarsomine Injections: After the doxycycline course, a waiting period of a month is recommended. Following this, the first melarsomine injection is administered, with two more injections given 24 hours apart, one month later.

Slow-Kill Method: Ivermectin

For owners who can’t afford melarsomine or are looking for a less aggressive treatment, the slow-kill method using Ivermectin (a heartworm preventative) can be an option. This method targets the immature worms, preventing them from maturing into harmful adults. While it doesn’t kill adult heartworms directly, it prevents the addition of new ones, letting the older worms die naturally over time.

Alternative Remedies: Natural Treatments

There are numerous discussions around the potential of natural treatments for heartworms. Some natural remedies suggested include:

  • Wormwood and Black Walnut: Wormwood contains tannins known to irritate parasitic worms. However, its efficacy against heartworms is still under debate, and wormwood can be toxic in high doses.
  • Food Supplements: Enhancing a dog’s immune system with herbs like garlic and turmeric can theoretically make the environment less hospitable for worms, although direct evidence is lacking.

Note: Always consult with a veterinarian before trying any alternative treatments.

The Importance of Prevention

An ounce of prevention is worth a pound of cure. Preventative medicines, like Ivermectin, Selamectin, and Moxidectin, are vital. Administered monthly, they kill larvae before they mature, offering an effective heartworm preventive measure.

Post-Treatment Care

After heartworm treatment, it’s crucial to restrict your dog’s activity. Excessive movement can cause the dead worms to dislodge, leading to potential blockages in the pulmonary vessels. Toys, chew sticks, and gentle training can keep your dog entertained without much physical exertion.


Dealing with heartworms is a challenge that requires a multi-pronged approach involving treatment, prevention, and post-treatment care. Always seek a veterinarian’s advice to determine the best course of action for your furry friend. Regular check-ups, prompt treatment, and preventive measures can ensure your dog stays heartworm-free and healthy.

FAQs: Heartworms in Dogs

1. How long can a dog live with untreated heartworms?

While some dogs can live for years with heartworm disease, the condition gradually deteriorates the heart, lungs, and liver. Over time, complications like congestive heart failure can arise, significantly reducing the dog’s lifespan. However, the severity and progression vary depending on the number of worms, the dog’s overall health, and age.

2. What are the early signs of heartworm infestation in dogs?

Early-stage symptoms might be subtle or even non-existent. However, as the disease progresses, signs might include:

  • Persistent cough
  • Fatigue after moderate activity
  • Loss of appetite and weight loss
  • Swollen abdomen due to fluid accumulation

3. Can humans get heartworms from their dogs?

Humans can be infected by heartworms, but it’s extremely rare. In most cases, the heartworm doesn’t complete its life cycle in humans. Instead, it migrates to the lungs, causing a lesion that looks like a tumor on X-rays. It’s vital to understand that humans do not get heartworms directly from their dogs. The transmission requires a mosquito as an intermediary.

4. Is it safe to adopt a dog that has been treated for heartworms?

Yes, it’s safe to adopt a dog that has undergone heartworm treatment. Once treated, and with proper post-treatment care, the dog can lead a normal and healthy life. However, ensure that you maintain regular heartworm preventive measures to avoid any future infections.

5. How often should dogs be tested for heartworms?

The American Heartworm Society recommends annual testing for heartworms, even for dogs on preventive medications. This ensures that the preventive measures are working and allows for early detection if they contract the disease.

6. Are there any side effects to heartworm treatment?

Melarsomine treatment can cause swelling and pain at the injection site. Some dogs might experience fever, lethargy, loss of appetite, or coughing as the worms die off. If you notice any of these symptoms post-treatment, it’s essential to consult your veterinarian immediately.

7. Do all mosquitoes carry heartworms?

No, not all mosquitoes carry heartworms. Only mosquitoes that have bitten an infected animal can transmit the larvae to other animals. The transmission cycle begins when a mosquito bites an infected dog, taking in the microfilariae (young heartworms) which then mature into larvae over 10-14 days. It’s only after this that the mosquito can infect other animals.

8. Is there a certain time of year when dogs are more at risk of getting heartworms?

While heartworm transmission occurs all year round, it peaks during the mosquito season, which varies by region. In warmer climates, the risk is consistent throughout the year, while colder areas might see a surge in warmer months.

9. Can puppies be born with heartworms?

Heartworms are not directly passed from mother to puppies in utero. However, puppies can get infected if bitten by a mosquito carrying the heartworm larvae. It’s why starting heartworm prevention early in a puppy’s life is crucial.

10. Are certain dog breeds more susceptible to heartworms?

No specific breed is more predisposed to heartworms. However, dogs with compromised immune systems or those in high-risk areas without preventive measures are at a heightened risk, regardless of their breed.

11. Why is early detection crucial for heartworm treatment?

Early detection is pivotal because the damage caused by heartworms is progressive. The longer they reside in a dog, the more harm they cause to the heart, lungs, and pulmonary system. Treating at an earlier stage can prevent more severe complications and lead to a higher likelihood of a full recovery.

12. How can owners reduce the risk of heartworm exposure for their pets?

To minimize exposure:

  • Ensure regular administration of heartworm preventives as prescribed.
  • Install screens on windows and doors to limit mosquitoes inside the home.
  • Avoid areas with high mosquito activity, especially during peak times like dusk and dawn.
  • Use mosquito repellents approved for pets.

13. If a dog’s heartworm test is negative, does it mean they’ve never had heartworms?

A negative test indicates that the dog doesn’t have an active heartworm infection. However, it doesn’t necessarily mean the dog has never had heartworms. If previously infected but effectively treated, the dog can test negative.

14. Can cats get heartworms, and is it the same as in dogs?

Yes, cats can get heartworms, but the disease manifests differently than in dogs. While cats are less susceptible, they can still get infected. The disease in cats is often misdiagnosed as asthma or bronchitis. Unlike dogs, there’s no approved treatment for heartworm in cats, making prevention even more critical.

15. Are there any natural preventive measures for heartworms in dogs?

While there are claims of natural remedies, like garlic or certain herbs, there’s no scientific evidence to back their effectiveness in preventing heartworms. It’s crucial to rely on proven preventive measures and consult with veterinarians regarding safe and effective options.

16. How long does the heartworm treatment process usually take?

The duration of treatment depends on the severity of the infection. A standard protocol involves administering doxycycline for 28 days, followed by melarsomine injections after a month. The entire process can take a few months, but it’s crucial to follow the vet’s guidelines for post-treatment care.

17. Is there a risk of heartworm reinfection after successful treatment?

Yes, if preventive measures aren’t taken, dogs can get reinfected after successful treatment. Heartworm prevention needs to be a continuous effort.

18. What’s the difference between ‘slow kill’ and ‘fast kill’ methods of heartworm treatment?

The ‘fast kill’ method uses melarsomine injections to eliminate adult heartworms rapidly. In contrast, the ‘slow kill’ approach uses ivermectin, a heartworm preventive, to gradually kill immature worms. While the ‘slow kill’ method might sound less aggressive, it doesn’t effectively eliminate all adult worms and may lead to prolonged damage.

19. Why is restricted activity advised during heartworm treatment?

As heartworms die off during treatment, they break into pieces. If a dog is active, there’s a risk of these fragments causing a blockage in the lungs, leading to a potentially fatal condition called a pulmonary embolism.

20. How do veterinarians test for heartworms?

There are a few diagnostic methods, but the most common is the antigen test, which detects proteins released by female heartworms into the dog’s bloodstream. This test is often combined with a microfilariae test, which checks for baby heartworms.

21. Why is there a focus on mosquitoes in heartworm transmission?

Heartworm larvae, known as microfilariae, are transmitted through mosquito bites. When a mosquito bites an infected dog, it can pick up these larvae. After maturing inside the mosquito for 10-14 days, these larvae are then transmitted to another dog when the mosquito feeds again. Thus, mosquitoes play an essential role in the heartworm life cycle.

22. Are all dogs equally susceptible to heartworm infection?

While all dogs are susceptible, some factors can increase the risk. Dogs living in humid and warm climates with higher mosquito populations are at a greater risk. Also, dogs that spend more time outdoors are more exposed to mosquito bites.

23. Is there a certain age when dogs are most vulnerable to heartworms?

Heartworms can affect dogs of all ages. However, puppies under seven months of age can start on preventive medication without a heartworm test, as it takes about six months post-infection for a dog to test positive.

24. Does a dog’s size or breed play a role in the severity of a heartworm infection?

While the severity can vary among individual dogs, there’s no concrete evidence to suggest a particular size or breed is more severely affected than others. However, some dogs might display more noticeable symptoms due to their physical characteristics or general health.

25. Are there specific signs pet owners should look for post-treatment?

Post-treatment, owners should be observant for coughing, fatigue, decreased appetite, or any unusual behavior. These could indicate complications or side effects, warranting immediate veterinary attention.

26. Why is there an emphasis on using preventives even in areas with cold winters?

While mosquitoes thrive in warm weather, they don’t necessarily die off in colder temperatures. They can go dormant in protected areas and can become active if there’s a brief warm spell. Thus, continuous prevention is key.

27. How do heartworm preventives work?

Heartworm preventives work by killing the larvae at the early stages of the heartworm life cycle. They don’t kill adult heartworms but prevent the worms from maturing and causing severe damage.

28. Can heartworms be transmitted from one dog to another without mosquitoes?

No, direct transmission between dogs isn’t possible. Mosquitoes are the primary vectors. A mosquito bite is necessary for the larvae to be transmitted and infect another dog.

29. If a dog is treated for heartworms, are they immune to future infections?

No, having a past infection doesn’t grant immunity. This is why ongoing preventive measures are crucial even after a dog has been successfully treated.

30. Are there any new research or treatments on the horizon for heartworms?

Research is continuous, with scientists exploring more effective and safer treatments, as well as better preventive measures. One area of focus is identifying potential resistance in heartworms to current preventive medications. Veterinarians remain the best source for updated information on advances in heartworm treatments and preventives.

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