Heartworms!
Oscar, the rescued golden retriever had his first treatment for heartworms yesterday. He came home rather tired from it all and as Regina, Sherrina and I stood around him while Regina told us about how the vet explained how the treatment should work, we were suddenly baffled by where the worms actually go to after they die???!!!
So here’s the inside story on heartworms (literally!)
Heartworm (Dirofilaria immitis) is a fairly large worm (up to 14 inches long) that, in adulthood, lives in the heart and pulmonary arteries of an infected dog. Dogs aquire this infection through mosquito bites as mosquitoes readily pick up larval heartworms from infected dogs and carry them to new dogs.
The adult heartworm prefers to live, not in the heart, but in the pulmonary arteries. It swims into a cozy tubular artery, where it is massaged and nourished by the blood coursing past it. In the pulmonary arteries of an infected dog, the worm's presence generates a strong inflammatory response and a tendency for blood to inappropriately clot. If enough worms are present, the heart must work extra hard to pump blood through the plugged up arteries.
If the worm infection is a heavy one (over 25 worms for a 40 lb dog), the worms begin to back up into the right ventricle (the chamber which pumps blood through the lung). The worms actually take up a significant amount of space within the heart, leading to less blood being pumped.
When over 50 worms are present, the ventricle is full and the atrium, the chamber receiving blood from the rest of the body begins to contain worms.
When over 100 worms are present, the entire right side of the heart is filled with worms and there is very little room for any blood to be pumped. This drastic phenomenon is called "Caval Syndrome" and most dogs do not survive it.
Well, prevention is definitely better than cure and there are a host of medications available in the market. Just have a chat with your vet with what’s suitable.
Moving on to treatment which involves managing the heart, vascular and systemic disease present as well as eliminating the parasites. The goal of treatment is to eliminate the worms one way or another so the animal’s body can rebuild itself and return to the best possible post-infection health. This sounds simple but it can be very complicated depending upon the number of worms present, the dog’s reaction to their presence, the patient’s general state of health, handling the side effects from the medication and the effects on the patient of the dead worms within the circulatory system.
By now, it is clear that the treatment varies from dog to dog. Each animal’s personal condition is evaluated and the treatment protocol tailored to best effect a full recovery with the least side effects. Therefore, this discussion of heartworm treatment will be very general regarding the medications used and the more common side effects. The specific treatment protocol for your pet will be left up to your veterinarian since there is no way to predict how each animal will react to Heartworm treatment.
Treatment involves two basic areas:
1st) Patient evaluation and stabilizing for treatment procedure.
2nd) Elimination of all forms (adult, larvae, and microfilaria) of the Heartworm parasite.
Patient evaluation and stabilization : This involves X-rays, blood tests, heart evaluation, and any other tests indicated to completely evaluate the pet. The veterinarian evaluates the over-all health of the animal, then determines how to best proceed with treatment. Part of this evaluation is staging the severity of the Heartworm Disease in the dog. Some animals need to have certain conditions stabilized before Heartworm treatment can proceed. Those in third stage Heartworm disease may require deliberation to decide if it is best to try surgical removal of some worms through the jugular vein before any other steps of parasite elimination are considered.
Elimination of the Heartworm Parasite : This is a two-step process. The adult worms and the microfilaria are eliminated separately. No one medication kills both. The adults are treated first then a different treatment is used to kill the microfilaria and migrating larvae. The most serious side effects usually occur with the treatment of the adult worms. As the worms die they lodge in the lung arteries and block even more blood vessels than before treatment. Besides the usual inflammation caused by the presence of the worms, the inflammation is amplified due to the decomposing worms within the blood vessels. This worm destruction releases foreign substances in to the dog’s circulation as the worms break down and are eliminated from the dog by the immune systems. A large amount of inflammation and swelling generally occurs during this period. There you go girls – the answer to our dilemma :)
Before treatment begins, it is very important to ask your veterinarian any questions you may have about the treatment and what to expect. Some veterinarians will keep the dogs in the hospital during treatments to watch them closely. The vet will make the decisions on an individual basis regarding what would be best for your dog.
The prescription medications used to treat the adult Heartworms are called adulticides. The two adulticides used most commonly are derivatives of arsenic. It is not known exactly how these medications work to kill the worms. We just know they do work.
And with that faith, we hope Oscar recovers beautifully and will be able to run the miles a dog his size should be. He has already put on two kilograms in two weeks with Regina’s careful care and is on the road to recovery!
View Complete Story >>
More Articles By Independent Pet Rescuers (IPR)
|
|
Member Login
