Heartworm in Cats

Cats might not be the natural hosts for heartworms, but keep in mind that the heartworm disease doesn’t only happen to dogs, we can also have heartworm in cats which leads to serious health complications.

Actually, a lot of current studies have shown, that in many areas of the USA the predominance of feline heartworm infection surpasses the rate of both feline leukemia virus (FeLV) infection and feline immunodeficiency virus (FIV) infection.

Nevertheless, no predominance studies have been made in Australian cats. The percentage of heartworm in cats depends on the number of heartworm contaminated dogs in the area. But the bright side of this situation is that your cat can be immune against this parasite with an easy spot-on treatment once a month.

A little definition of Heartworm Parasite:

The parasite lying behind the Heartworm disease in cats is Dirofilaria immitis, it’s a parasite that infects dogs by nature. The adult worms living in the heart produce progeny named microfilariae. They circulate in the bloodstreams of the infected pet and are spread by mosquitoes while feeding.

They develop inside the mosquito into contagious larvae and when fed by the mosquito these larvae are transferred to the new host. During the first 3 to 4 months the larvae transform into immature worms and then emigrate to blood vessels in the lungs and to the heart where they get mature and generate more offspring, to start their life cycle all over again.

Why is there a difference between Heartworm in Cats and Heartworm in Dogs?

Not being the parasite natural host makes the reaction of cats to this disease different than the dog’s, they develop a very powerful immune reaction aimed against young worms. In general, that response is the one responsible for the apparent symptoms of the heartworm in cats, instead of the presence of adult worms in the heart.

If it’s a cat the correct name of the disease is Heartworm-Associated Respiratory Disease (HARD ), because in dogs case heartworm disease is heart disease, while in cat’s case it’s a lung disease since that is the place where young worms live.

The toughest immune response generated caused the development of inflammatory cells into the lung tissue. This restrains the natural lung function which is transferring carbon dioxide out of the body and oxygen into the bloodstreams.

This can cause many heartworm symptoms in cats such as inactivity and fragility, the loss of appetence, the loss of weight, coughing, puking, difficulty of breathing, loss of consciousness or even unexpected death.

These symptoms are not particular to heartworm in cats and sometimes HARD can be misdiagnosed as cat asthma.

If some worms make it and become adults, and generally they are few, It takes 2 to 3 years, versus 5 years for dogs, to die. When worms die they reduce to pieces, which might reside in blood vessels and form clots. This can be the cause lying behind serious complications in many vital organs including the kidneys and the brain and we certainly start wondering for how long can a cat live with heartworms?

Just like the cat’s body had an immune reaction to the worm ans shows more than one sign of heartworm in cats; it has the same for its pieces, which might cause a huge life-threatening inflammatory disease.

One of the reasons of not advised to treat the heartworm in cats by killing the adult worm is the atrocity of the consequences of having pieces of the worm in the bloodstreams; as around one of three treated cats can have life-threatening reactions.

How to diagnose the Heartworm Infection in Cats?

It’s harder to diagnose the heartworm in cats than it is in dogs. The regular blood test in dogs can reveal the presence of a protein the female worm produces in the blood, thus the presence of worms.

While on the other hand, in cats, fewer worms succeed to live until adulthood, and the few left females produce that protein in such a small amount that it can’t be detected in the blood test, let alone if no female worm stays alive and only male worms live in the cat, there will be no protein at all in the blood, thus a negative blood test.

Similar tests were put together to detect microfilariae in the blood failed as this depends on the presence of adult worms of both sexes to produce offspring.
Moreover, the cat’s strong immune reaction to the heartworm in cats rapidly clears microfilariae.

Another blood test was made to detect antibodies developed by the immune system against the worms remaining in the infected cat’s body, it’s a brilliant way, but knowing that an antibody can survive in the body for so many years after the virus vanishes, a positive test isn’t really giving enough information about whether or not the virus is still in the bloodstreams.

Add to this, that in the early stages of the heartworm in cats, the antibodies take time to develop, hence a negative test.

Currently, the diagnostic of HARD requires a combination of clinical signs and antigen testing; in case the test comes negative the resort would be antibody testing and chest imaging (X-rays and ultrasound of the heart).

Is there a possibility to cure heartworm in cats?

This treatment, in general, leads to killing off adult worms in cats, and due to the high risks resulting from that, it’s highly disapproved. The clinical signs of HARD are mostly due to the overactive immune reaction, immune restrainer such as cortisone may be prescribed to relieve the symptoms and the adult heartworms in cats are left to end with natural death.

We can monitor lung disease by chest X-rays almost every 6 months depending on the atrocity of symptoms.
However do not fear, it’s not impossible to prevent heartworm in cats!

Heartworm in cats prevention includes secure and efficient preventative treatments, which are extremely available to kill larvae on infection. They should be given to all cats during their entire lives.

Do indoor cats get heartworms?

Even though the risk of having the heartworm in cats could be minor in indoor cats they can certainly still be contaminated since all it takes is one random mosquito bite. So it’s preferable not to risk and make sure your cat gets all the preventive treatments.

Add Comment