The Doctor Will See You Now

I never intended to be this earnest or specific, never expected to offer any advice whatsoever about dogs, but my rescue mutt and I are going through something in real time that I think is worth sharing.  Willie has been diagnosed with parasitic heartworms – a highly preventable, dangerous, and potentially fatal infection.  And I am educating myself about the condition and its treatment outcomes since I am Willie’s advocate, his voice, and his best friend.

Until relatively recently, the only tool doctors had to fight heartworm was arsenic – specifically, an arsenical compound injected deep into the dog’s lumbar muscles, followed by a second injection some time later.  This killed the worms, but it also sickened – and sometimes killed – the dogs.  Which reminds me of that old Vaudeville joke where “the patient died, but the surgery was a success.”

Reading about all this struck me as something similar to chemotherapy – a necessary evil whose potential benefits outweighed its risk (in this case, the risk being choosing to do nothing).  There are different protocols using this drug – a fast-kill and a slow-kill approach.  The fast kill would eliminate all the worms at once, but could overwhelm the dog’s organs (imagine the valves or chambers of your heart clogged with vermicelli).  The slow-kill method is a staged approach, with a lower dose of the drug administered in a couple of visits, maybe a month apart.  This is easier on the dog, and while it kills the “microfilaria” or the tiny, early stage heartworms circulating in the bloodstream, it leaves the existing, adult heartworms to live out their natural lifespan – a period of one to three years.

If I understand this correctly (and correct me if I’m wrong), The American Heartworm Council now advocates a protocol that begins with a couple of weeks of an antibiotic (doxycycline, or “doxy”) – pills administered to the dog twice a day that are intended to kill off a bacteria called Wolbachia that’s naturally present in the gut of the heartworm.  This weakens the worms and likely shortens their lifespan.  The second line of attack is to also administer a low dose of Immiticide — a once-a-month heartworm preventive like HeartGuard.  That kills off the microfilaria – the “babies”, while leaving the adults in place to live out their lives – likely one to two years.

Now, the idea of a “treatment” that leaves adult worms living in my dog’s body is both repugnant and scary – rather like being told it’s best to allow an ugly tumor to continue to grow.  But the alternative – killing everything at once — seems worse.

And so I put my faith in the advice of the vet.  I pick up my wagging pup, reach for my car keys, and head for the door.