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Heartworms can be deadly but heartworm prevention is a decision dog owners should make based on this rarely-revealed, facts-first, side-effects information.





Barbara J. Andrews, SAAB Member


Heartworms can be deadly but heartworm prevention is a decision dog owners should make based on this rarely-revealed, facts-first, side-effects information.


Millions of owners agree to heartworm prevention “medication” without being informed of (1) the odds of heartworm infection, (2) the health risks involved, or that (3) heartworm treatment may not be as effective as expected in preventing heart damage.



The American Heartworm Society {Ref #1} admits to a “lack of efficacy” (LOE) in preventing heartworms. Buried in a long page of fine print are scattered statements such as “There is also biological variation in how hosts within the same species metabolize a drug and host immune response to parasites, as well as how parasites respond to a drug. Thus, the cause of a reported LOE of a product can be extremely difficult to determine.


The report then cautions veterinarians to make sure their clients understand the “implications of heartworm infection” and “the risk of heartworm infection in their area.” The vet rarely explains the potential medical problems created by the systemic poison.


As an aside, if anyone reading this has ever been told “their area” is low risk and that heartworm preventative need not be given, please email the editor! That would be a FIRST! The American Heartworm Society continues with the “critical” advice to ensure that clients are “providing their pets with appropriate year-round heartworm prevention.” 2/3 of the U.S. has winter weather that prevents mosquitoes but apparently some veterinarians don’t understand the science, only what’s good for sales.


I read with an eye trained to spot quantified facts instead of verbiage that carefully skirts an issue or is designed to obscure the reader’s perception of fact. Therefore, I’m intrigued by the lack of efficacy (LOE) admission combined with the suggestion that people should administer a systemic poison to their dogs year-round.


If there is an upside to the risk, it is that being on heartworm prevention gets the dog to the vet for regular checkups.


Marketers of “heartworm prevention” say dogs are not being testing frequently enough and accurately point out that due to the long maturation process, a dog could test clear but actually be infected.


On that basis, it is recommended that re-testing is conducted up to three times per year. We must assume that is also meant to explain away any dog found to be heartworm positive while it was being treated.


That happens but of course it is blamed on the owner’s failure to faithfully or properly administer the heartworm prevention “medication”. The heartworm society cites owner error in missed doses and therefore, now recommends YEAR-ROUND DOSING no matter where you live. That means your dog should be treated 365 days, no break. Good for the heartworm “prevention” makers, good for the veterinary practice, good for the dog to be seen regularly IF the checkup doesn’t result in more and more medicines…


As a Floridian, I weighed the odds of (1) my dogs being bitten by a mosquito carrying heartworm larvae (2) whether the larva ever makes the long journey to the heart and (3) how many larvae actually mature so as to potentiate damage - as compared to the certainty of poisoning my dog every day.


I decided against heartworm “prevention” based on 3 definitive, inarguable real-life reasons.


In the late 60s, we managed a small racing greyhound kennel for absentee owners. All the big racing kennels immediately ordered the new miracle styrid caracide. Even though we were in mosquito-infested Florida, the owners, who were also Rottweiler breeders and very much of the old German school, said “let’s wait.


Within six months there wasn’t a racing kennel in the U.S. that used the “heartworm preventative” (sheep wormer). Greyhound breeders and trainers are among the most dedicated to canine care and diet. Their litters didn’t thrive. Bitches missed. Track times went off by as much as 2 seconds. 92% ceased using the styrid caracide or any other systemic poison.


A few years passed and we were living next door to dog-friends whose property had a small, stagnant pond. Worried about the mosquitoes, we decided to get our dogs heartworm tested. One of their four Dobermans tested positive but she was 7 years old and our vet advised against putting her on styrid caracide. Bill and I had an older Doberman and two adult Rotties. All were negative. We played poker a lot back then and after weighing the odds, the four of us decided 1 out of 7 was pretty good.


Their beloved Tessa, heartworm infected but not treated, lived to 13 and none of our dogs “caught” heartworm.


Heartworm prevention has saved millions of dogs from the disease. Significantly, I could find no statistics on the incidence among untreated dogs. Whatever, I’m going to guess that for every untreated healthy dog there is at least one dog on heartworm preventative that is NOT healthy.


I say that with a degree of certainty gained after recently observing a waiting room full of obese, hairless, itching, allergic dogs during a two-hour wait in the vet’s office. I casually asked if I should consider heartworm prevention. Several of those owners said yes.


I make no recommendations either way. I just thought you might like to know some of the risks so you can make your own informed decision.



Copyright ? 1998 2001-2021   2105



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