Heartworm Prevention and Treatment

As a pet owner, you understand the value of your furry companion's well-being. Just like humans, pets can also fall ill and be affected by diseases and infections. One common health issue that pets face is worms, and heartworm is one of the most dangerous worms that can enter your pet's body and pose a threat to his life. Heartworm is transmitted through mosquito bites. The good news is that a veterinarian can test your pet and provide treatment at an animal hospital. At Alum Rock Animal Hospital in San Jose, our dedicated team offers preventative care for your pet, including blood tests, scans, and emergency services. 

Heartworm treatment

Understanding Heartworm

Heartworm is a worm that is transmitted to pets through mosquito bites. Once the worm enters a pet's body in its larval stage, it matures in the organs over a period of 5-6 months. The larva travels through the bloodstream to the heart and lungs. The adult worms reproduce, producing young worms called microfilariae, which are released into the bloodstream. When a mosquito bites an infected pet, it picks up the microfilariae and passes them on to its next victim. If you live near water bodies, preventing mosquito bites on your pet can be challenging. Research shows that prevention is the best way to control heartworm, so it's important to eliminate mosquito breeding areas around your home as much as possible.

Signs of Heartworm in Pets

Detecting the signs of heartworm in pets can be challenging initially. It may take months or even years before you notice that your pet is harboring worms in his body. By the time signs become apparent, your pet may have a significant number of heartworms, known as a heartworm burden, which can reach up to 250 worms. Heartworms affect the function of the heart valves, disrupting blood circulation. It can block blood vessels leading to the heart (known as caval syndrome), causing the heart to work harder and potentially become enlarged and fatigued.

Some common signs to watch out for include:

    • Chronic fatigue
    • Shortness of breath
    • Persistent dry cough
    • Worsening breathing difficulties if left untreated
    • Swollen abdomen due to fluid accumulation
    • Loss of appetite and weight in dogs

Regularly checking for these signs should be a part of your pet care routine. However, it can be challenging to notice these symptoms in many cases. Therefore, prevention of worm infestation is the best approach. Treatment can be risky, and without proper veterinary care, your pet's life may be at stake.

Cats display fewer signs when infected with heartworms. Loss of appetite, weight loss, and coughing are the most common signs in felines. However, sudden death is more likely, especially if the cat has gone untreated for an extended period. Even one or two adult worms in a cat can be fatal.

Preventative Care

Preventative medication for heartworm is available. If you haven't taken your dog for heartworm medication in over six months, it is essential to do a blood test before starting treatment. Administering preventative treatment without a test may be ineffective if your dog already has heartworms. Ideally, begin prevention treatment when the pet is around 6-8 weeks old.

The veterinarian can administer the treatment once a year through injections, tablets, or top spot applications. Injections are the preferred option for dogs, while top spot applications or tablets are more suitable for cats. Administering medication to cats can be challenging, so it's best to seek expert help. Heartworm medication is available that also prevents fleas and intestinal worms in cats and dogs.


When you bring your pet to a veterinarian, we will conduct a blood test to determine if it is infected with heartworms. However, diagnosing heartworm in cats can be more challenging. The best approach is to prevent the worms from entering your pet's body. Ensure your pet receives regular heartworm medication and schedule frequent checkups at an animal hospital.


Treatment for heartworm is available but can be expensive, involving continuous injections, hospitalization, x-rays, blood tests, and multiple visits to the veterinarian. The treatment can also pose risks to dogs, such as allergic reactions or blood clots in the lungs. Prevention is generally the best choice to avoid these complications.

Contact Us for Exceptional Veterinary Services

For affordable and excellent heartworm preventative medication, diagnosis, and tests, contact Alum Rock Animal Hospital at (408) 258-2735. Pet care is our passion, and our highly dedicated veterinarians in San Jose are ready to help you provide preventative care for your pet and keep it safe from these harmful parasites. We are also available for pet emergency care.