treating Heartworms in Cats

Heartworms in Cats – Preventing and Treating Them

Heartworms are not easy to detect because symptoms appear slowly.

You’ll just know if your cat contracted the disease when it’s already too late.
This is why the most effective treatment for heartworms is prevention.

Protecting them and keeping them healthy is better (and cheaper too) than treating them when they’re already infected.

Heartworm Disease -What You Need to Know

Dirofilaria immitis is commonly known as heartworm, and is a parasitic nematode (they belong to the roundworm family) that infects animals, especially cats and dogs.
Heartworms are thought to be only found in dogs.

However, studies reveal that cats displaying heart and respiratory diseases become more prone to the infection.

Still, dogs are more likely to contract the disease compared to your feline companions.
Multiple worms can reside on any one animal.

They live in the heart and neighboring blood vessels of the infected animal.

Heartworms usually have lengths ranging from 6-14 inches and thickness of about 1/8 of an inch.

They can live up to 3 years inside your cat’s body which is quite long if you compare it to other parasites.

It takes only 6 months for the larva to mature into an adult heartworm.

Adults can reproduce and this is bad news for your cat.

Their effect multiplies depending on their number and how long they’ve been living inside your cat’s body.
The species of heartworm found in cats are a little smaller, have shorter life cycles, and don’t multiply as fast compared to those found in dogs.

This is why cats infected with heartworm disease are more likely to recover from it without any intervention.

Their immune system can counteract the spread of heartworms, making them more resilient to the disease as compared with dogs.

However, infection should not be taken lightly.

They can greatly alter your cat’s life.

Severe cases may result in shortened lifespan and sudden death.

Where Can Your Cat Get It?

Mosquitoes are the primary carriers of heartworms.

They get it from sucking the blood of an infected animal.

The heartworm eggs are transferred into the mosquito’s body, making it its new home.
Heartworm eggs hatch inside the mosquito’s body and grow into larvae.

The larva grows and then crawls into the digestive tract of the insect, giving them access to move to the mouth of the mosquito.
The infected mosquito then bites a healthy cat, transferring the larva into the body of the new host.

As the larva transforms into its adult form, it migrates toward the heart and large blood vessels of the cat.

It resides and reproduces there, further harming your cat’s health.
The disease can’t be directly transmitted from one cat to another.

Heartworms need a carrier to suck them from one cat and inject them into another.

This is why cats roaming outdoor are more likely to get bitten by an infected insect.

Effect on Cats

The early signs you can look for in infected cats include difficulty in breathing, frequent coughing, and vomiting.

Heart murmur or irregular heartbeat is also a sign your cat has heartworm.
In worse cases, seizures and fainting may happen.

Difficulty in walking and enlarged abdomen due to the accumulation of fluids may also be observed in cats suffering from multiple heartworms.

If left untreated, the heartworms can even cause death.

Testing for Heartworm

Sad to say, there’s no accurate way to determine if your cat has a heartworm.

Even a series of clinical tests can’t absolutely detect the presence of these parasites.

This is another reason why prevention is better than cure when this disease is involved.
Multiple blood tests can be done to determine if your cat really has heartworm.

  • Antibody test ‘ determines the number of antibodies your cat has produced in response to fighting the disease.
  • Antigen test ‘ helps determine the presence of a female heartworm in your cat’s body.
  • Eosinophil count ‘ an increase in the number of white blood cells may mean a parasite has been detected by your body and is continuously fighting to destroy it.

Cats infected with the disease exhibit enlargement of the arteries.

An ECG can be done on the heart and pulmonary artery to determine if there are any objects blocking the passageway of the blood.

Echocardiography and ultrasounds can also be performed to give the veterinarian a better view of the vessels connected to the heart.

This is not often used, though, because it can’t detect the presence of small heartworms in the body.

Preventive Measures

Aside from being cheaper than getting your cat hospitalized, preventive measures ensure your cats don’t have to suffer from the life-altering effects of heartworm infection.
As discussed, there’s no evident measure to determine heartworm infection 100% of the time.

It remains difficult to diagnose to this day since symptoms may also be caused by other diseases.

Even blood tests and x-rays can’t fully detect the presence of heartworms in an infected pet.

For more bad news, there’s no known treatment for heartworms.

The available medications on the market may not completely cure your cat of the disease.

Some drugs may even cause adverse reactions and introduce other illnesses during the treatment period.

Preventive measures can be started on kittens as young as 6 weeks old.

This is the best time to start shielding them from the disease as they have no history of the infection yet.
Cats living in areas frequented by mosquitoes should be given care all the time.

For areas where mosquitoes are seasonal, treatment every 6 months is strongly suggested.
It’s true that cats who roam outside the house have higher chances of getting heartworms.

However, indoor cats are still not safe from contracting the disease.

Infected mosquitoes may still enter the house and get in contact with your pet.

Make sure your home is mosquito-free and you give your cats preventive treatments regularly.

Available Medications

There are many preventive drugs clinically tested to help strengthen your cat’s immunity against the disease.

They’re often available in oral and topical forms.
Oral medications are often recommended by veterinarians over other drug forms.

They’re more effective and rarely cause any side effect.

For cats experiencing side effects, they may exhibit diarrhea and vomiting for a short period of time.

Topical solutions are quite new to the field.

They have more benefits, though, compared to oral solutions.

They may also act as flea control and may exterminate other forms of parasites aside from heartworms.

This is a good combination as you can remove all pests that deteriorate your cat’s health in just one go.

Ointments should be applied to areas where your cats can’t reach.

Their shoulder blades is a good area as they can’t lick this portion during self-grooming.

Make sure you also keep the cat you’re treating away from other animals for at least 30 minutes.

This is to prevent others from ingesting the solution when they come in contact with the treated cat.
Before giving your cats any medication, make sure to get approval from your veterinarian first.

This is to ensure you’re giving your pets the right dosage.

Also, cats that already have heartworm disease won’t properly respond to preventive medicines.

They will need to undergo a different kind of treatment process to restore their health.

Treatment for Severe Cases

To repeat, there’s no drug that can absolutely cure heartworm disease.

Some may suggest giving your cats the heartworm drug used in dogs.

This is not a good idea as it can introduce other complications and side effects.

Even if they prove to be effective, the dead heartworms will be pumped through the pulmonary veins, causing a blockage which can lead to death in severe cases.

Another option is to respond to the symptoms with the hope that your cat outlives the heartworm.

There is a slim chance, though, for this to be successful as heartworms can multiply inside the cat’s body.

The last option is surgery.

This can prove to be very effective but the process is still in its early phases.

It has a high reward-risk ratio which you may not be willing to gamble your pet’s life on.


There is no known cure for heartworm disease.

Even the symptoms are not reliable enough to determine whether your cat already has the disease or not.
As with any illness, prevention is better than cure.

This way, you’ll save your pet from unnecessary pain and save your wallet from expensive treatment processes.

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