And here we were, thinking happily that the Heartworm discussion was over – after six columns dealing with this dreaded disease. Well, the world is not made up of only dog lovers. Believe me, I have made this point over and over – just as I had mentioned in the first episode that cats do in fact contract Heartworm infestations, but rarely (see “PET CARE,” September 18 and 25, 2022). But “rarely” does not mean “never”. So, I must admit that some comments on the possibility of Feline Heartworm infections are worthy of being taken on board any discussion on this scourge.
We have established that the Canine Heartworm Disease (CHD) is common and ubiquitous in Guyana, especially where mosquitoes abound – which seems to be everywhere. As mentioned above, cats can become infected with HD, but on very rare occasions. I myself, after decades of practice, have never knowingly been confronted with HD in cats, nor has any colleague of mine reported such. Cats seem to be accidental hosts, if and when they are infected. Similar to the infection method in dogs, mosquitos – hosting infective immature stages (larvae) of the Heartworm in their saliva – will transmit the larvae when the mosquito bites the cat. These larvae then burrow their way into the body of the cat, where they undergo structural changes, becoming later adult worms which then get into the blood circulatory system and thence to the cat’s heart. I should mention that this process can take 6 months and more.
Again, as in the case of dogs, the adult Heartworms produce offspring (microfilariae) which circulate in the blood stream. Your vet can take a blood sample, and with the aid of the microscope, find these microfilariae (immature stages of the worm) wriggling around in the droplet of blood on the slide
Q:What are the
symptoms of the Heartworm Disease in cats?
A: Clinical Signs are:
• Coughing
• Respiratory Distress (asthma-like attacks)
• Inappetence (loss of appetite)
• Vomiting/gagging (sometimes with blood)
• Lethargy (listlessness; not exhibiting the usual energetic playfulness)
• Weight loss
• Incoordination of movement (difficulty walking)
• Ascites (fluid in the abdomen)
Q:What is the treatment?
A: Well, some bad news. There is no effective treatment. Of course, the caregiver (under veterinarian advice) can use medical interventions appropriate in reducing the severity of the symptoms. Again, your veterinarian will introduce medication that can help with the destruction of the adult worms and the immature stages, the same as for dogs, with different dosage rates, of course.
I have seen natural HD medication in Pet Stores in the USA. I will continue to rely on the cautious administering of science-based pharmaceutical drugs that bring about helpful (tested and proven) results. If clients insist on the use of herbal formulae, vets may guide them towards those natural products available, without advocating or endorsing their use.
Q: Can cats survive HD?
A: Yes. I say this tongue in cheek. The literature says that the cat’s immune system is geared for survival. This I do believe. I left my own cat when she was 8 years old, and returned 14 years later – and there was half-blind “Millicent”, still catching rats. It seems that the Heartworm in about 80% of infected cats may clear up without medication within 2-4 years after diagnosis.
Q: Is Feline HD
contagious to humans?
A: No. The Heartworm microfilariae die going through the human skin, and those which might get into the blood stream (of humans) will never mature into the adult form, and would soon die.
Q: Do cats have heavy
bundles of Heartworm
living in the heart chambers and large blood vessels?
A: No. But since cats’ hearts are comparatively small, even a few worms residing in the heart’s chambers can cause mechanical damage, as well as compromise the optimal function of the heart – simply by congestion (Heartworms physically taking up space). Cats, it seems, are really imperfect hosts for Heartworms.
