Continued form last week
Well, let’s see what we have learned about that rapidly spreading scourge of heartworm.
Firstly, we know that it is transmitted by mosquitoes, Secondly, we know that the adult worms (bundles of them) live in the right heart chambers (and sometimes in some of the big and important blood vessels), thus greatly compromising the function of the heart. Thirdly, and very importantly, we know that this disease (ie, the development of the visible symptoms) sneaks up on the poor animal, and by the time we begin to see signs of the ailment, the efficiency of many organ systems (liver, kidney, lungs, the heart itself) is impaired.
Lastly, we had documented that the main symptoms were (i) a soft, deep cough, (ii) lethargy, (iii) loss of condition (weight loss), and (iv) sometimes a swelling of the limbs (especially the hind legs).
So how do we keep tabs on the possibility of this disease developing?
Simple, we check the blood regularly. Your veterinarian can take a droplet of blood and examine it. Once the microfilaria (the immature stages of the heartworm) are seen, that is indicative of the presence of adult heartworms in the right heart chambers and possibly in large blood vessels as they leave the heart.
But you remember last week I said that this laboratory diagnosis is not straightforward. For one thing, if you don’t find these immature stages of the heartworm in the blood sample, that does not mean that there is no heartworm. Let’s give the reasons why this so:
(i) Some of our veterinarians are using, as a general dewormer, exactly the same drug that kills the microfilaria (immature stages of the heartworm)! This means that if this very efficient drug kills the microfilariae, then the vet won’t find them when the blood sample is observed under the microscope; yet the adults would be still existing in the heart quite happily, thank you (the drug does not kill the adult heartworm). This is a terrible state of affairs, and at the very next Vet Association meeting, this topic will be raised with the objective of correcting this… incorrectness.
(ii) The amount of microfilaria that are circulating at the time of sample taking might be so small that they will not be easily picked up during the microscopic examination of the blood droplet.
(iii) Some dogs actually have an immune system that is so strong that it develops antibodies that can kill the microfilaria.
(iv) At the time when the blood sample is taken, the worms in the heart might not have reached the stage of actual sexual maturity. In order words, they were not quite adult and therefore could not mate and produce the microfilaria.
(v) Lastly, and remotely possible, the worms in the heart could be of one sex only (all males or all females). Conse-quently, they would be unable to mate and reproduce offspring (microfilaria).
What does all of this demand of your veterinarian?
Simply put, your veterinarian must make it a part of his or her routine examination to check the dog’s blood for this parasite. This means (which can be deduced from the points made above) that the samples must be taken at regular intervals. It also means that if, after several blood checks, there is no sign of the microfilaria then, and only then, prophylactic measures (medication) should be administered. If, on the other hand, the presence of a heartworm burden has been identified, then therapy must immediately be introduced – or our dog will die a slow and excruciating death (guaranteed!).
The prevention and cure of heartworm disease will be dealt with next week.
Please implement disease preventative measures (vaccinations, routine dewormings, monthly anti-heartworm medication, etc) and adopt-a-pet from the GSPCA’s Animal Clinic and Shelter at Robb Street and Orange Walk, if you have the wherewithal to care well for the animals. Do not stray your unwanted pets, take them to the GSPCA’s Clinic and Shelter instead. If you do not wish your pet to have puppies or kittens, you may exploit the GSPCA’s free spay and neutering programme. If you see anyone being cruel to an animal, or if you need any technical information, please get in touch with the Clinic and Shelter by calling 226-4237.